Merge ram_console into pstore, and more
Subsystems (3)
v4 cover Merge ram_console into pstore, and more
Hi all,
A brand new v4:
- Per Kees Cook's comments, the patches no longer remove an automatic updates feature, but instead make the it configurable; plus disable it by default (in a separate patch);
- Fixed some bugs noticed by Colin Cross;
- Documented new continuous ramoops-console log behaviour (also noticed by Colin Cross).
In v3:
- Rebased on top of current staging-next;
- The series are getting bigger. This is partly because we now support different persistent zone sizes for oops records and console log, per Colin Cross' request.
And I believe the code is now more manageable for further enhancements (e.g. if we'd want to add other message types, e.g. tracing);
- Addressed Kees Cook's comments on the unlinking matters;
- Removed automatic updates support. Please see the last patch description for rationale;
- A new fixup for pstore/inode, just getting rid of a sparse warning.
In v2:
- Updated documentation per Colin Cross' comments;
- Corrected return value in ramoops_pstore_write() (noticed by Kees Cook);
- Fixed large writes handling in pstore_console_write(), i.e. when log_buf write is larger than pstore bufsize. Also Noticed by Kees Cook.
And a boilerplate for the series:
Currently pstore doesn't support logging kernel messages in run-time, it only dumps dmesg when kernel oopses/panics. This makes pstore useless for debugging hangs caused by HW issues or improper use of HW (e.g. weird device inserted -> driver tried to write reserved bits -> SoC hanged. In that case we don't get any messages in the pstore.
This series add a new message type for pstore, i.e. PSTORE_TYPE_CONSOLE, plus make pstore/ram.c handle the new messages.
The old ram_console driver is removed. This might probably cause some pain for out-of-tree code, as it would need to be adjusted... but "no pain, no gain"? :-) Though, if there's some serious resistance, we can probably postpone the last two patches.
Thanks!
---
Documentation/ramoops.txt | 14 ++ drivers/staging/android/Kconfig | 5 - drivers/staging/android/Makefile | 1 - drivers/staging/android/ram_console.c | 179 -------------------------- fs/pstore/Kconfig | 7 + fs/pstore/inode.c | 5 +- fs/pstore/platform.c | 49 ++++++- fs/pstore/ram.c | 228 ++++++++++++++++++++++++++------- fs/pstore/ram_core.c | 108 +++------------- include/linux/pstore.h | 1 + include/linux/pstore_ram.h | 22 +--- 11 files changed, 272 insertions(+), 347 deletions(-)
Signature · 2 lines
Anton Vorontsov Email: [email protected]
PATCH v4 1/16 pstore/inode: Make pstore_fill_super() static
There's no reason to extern it. The patch fixes the annoying sparse warning:
CHECK fs/pstore/inode.cfs/pstore/inode.c:264:5: warning: symbol 'pstore_fill_super' was not declared. Should it be static?
--- fs/pstore/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
fs/pstore/inode.c +1 -1
@@ -258,7 +258,7 @@ fail:return rc; } -int pstore_fill_super (struct super_block *sb,void *data,int silent) +static int pstore_fill_super (struct super_block *sb,void *data,int silent) {struct inode *inode;
Signature · 1 line
1.7.9.2
Re: [PATCH 01/16] pstore/inode: Make pstore_fill_super() static
Quoted 8 lines · Anton Vorontsov
There's no reason to extern it. The patch fixes the annoying sparse warning:
CHECK
fs/pstore/inode.cfs/pstore/inode.c:264:5: warning: symbol 'pstore_fill_super' was not declared. Should it be static?Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 2/16 pstore/ram: Should update old dmesg buffer before reading
In reply to Anton VorontsovWithout the update, we'll only see the new dmesg buffer after the reboot, but previously we could see it right away. Making an oops visible in pstore filesystem before reboot is a somewhat dubious feature, but removing it wasn't an intentional change, so let's restore it.
For this we have to make persistent_ram_save_old() safe for calling multiple times, and also extern it.
--- fs/pstore/ram.c | 2 ++ fs/pstore/ram_core.c | 15 ++++++++------- include/linux/pstore_ram.h | 1 + 3 files changed, 11 insertions(+), 7 deletions(-)
fs/pstore/ram.c +2 -0
@@ -106,6 +106,8 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, time->tv_sec =0 ; time->tv_nsec =0 ; +/* Update old/shadowed buffer. */ +persistent_ram_save_old (prz); size =persistent_ram_old_size (prz); *buf =kmalloc (size,GFP_KERNEL );if (*buf ==NULL )
fs/pstore/ram_core.c +8 -7
@@ -250,23 +250,24 @@ static void notrace persistent_ram_update(struct persistent_ram_zone *prz,persistent_ram_update_ecc (prz, start, count); } -static void __init -persistent_ram_save_old (struct persistent_ram_zone *prz) +void persistent_ram_save_old (struct persistent_ram_zone *prz) {struct persistent_ram_buffer *buffer = prz->buffer;size_t size =buffer_size (prz);size_t start =buffer_start (prz); -char *dest; -persistent_ram_ecc_old (prz); +if (!size) +return ; - dest =kmalloc (size,GFP_KERNEL ); -if (dest ==NULL ) { +if (!prz->old_log) { +persistent_ram_ecc_old (prz); + prz->old_log =kmalloc (size,GFP_KERNEL ); + } +if (!prz->old_log) {pr_err ("persistent_ram: failed to allocate buffer\n" );return ; } - prz->old_log = dest; prz->old_log_size = size;memcpy (prz->old_log, &buffer->data[start], size - start);memcpy (prz->old_log + size - start, &buffer->data[0 ], start);
include/linux/pstore_ram.h +1 -0
@@ -75,6 +75,7 @@ struct persistent_ram_zone *persistent_ram_init_ringbuffer(struct device *dev,int persistent_ram_write (struct persistent_ram_zone *prz,const void *s,unsigned int count); +void persistent_ram_save_old (struct persistent_ram_zone *prz);size_t persistent_ram_old_size (struct persistent_ram_zone *prz);void *persistent_ram_old (struct persistent_ram_zone *prz);void persistent_ram_free_old (struct persistent_ram_zone *prz);
Signature · 1 line
1.7.9.2
Re: [PATCH 02/16] pstore/ram: Should update old dmesg buffer before reading
Quoted 10 lines · Anton Vorontsov
Without the update, we'll only see the new dmesg buffer after the reboot, but previously we could see it right away. Making an oops visible in pstore filesystem before reboot is a somewhat dubious feature, but removing it wasn't an intentional change, so let's restore it.
For this we have to make
persistent_ram_save_old()safe for calling multiple times, and also extern it.Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 3/16 pstore/ram_core: Do not reset restored zone's position and size
In reply to Anton VorontsovOtherwise, the files will survive just one reboot, and on a subsequent boot they will disappear.
Also, as noticed by Colin Cross, this also causes an interesting behavior change in the console logging. Before this change, the console log would show only the messages from the last reboot. After this change, the console log will have logs from multiple boots appended to each other.
Now to get the only most recent messages we can do:
tac ramoops-console | sed '/^Linux version.*(.*@.*)/ q' | tac
--- fs/pstore/ram_core.c | 1 + 1 file changed, 1 insertion(+)
fs/pstore/ram_core.c +1 -0
@@ -406,6 +406,7 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool" size %zu, start %zu\n" , buffer_size(prz), buffer_start(prz));persistent_ram_save_old (prz); +return 0 ; } }else { pr_info("persistent_ram: no valid data in buffer"
Signature · 1 line
1.7.9.2
Re: [PATCH 03/16] pstore/ram_core: Do not reset restored zone's position and size
Quoted 11 lines · Anton Vorontsov
Otherwise, the files will survive just one reboot, and on a subsequent boot they will disappear.
Also, as noticed by Colin Cross, this also causes an interesting behavior change in the console logging. Before this change, the console log would show only the messages from the last reboot. After this change, the console log will have logs from multiple boots appended to each other.
Now to get the only most recent messages we can do:
tac ramoops-console | sed '/^Linux version.*(.*@.*)/ q' | tac
Lots of problems with this.
"Linux version ..." is not the first line in the console log on my devices, there are messages before it that shouldn't be dropped by automated logs collectors using this regexp.
There is a timestamp before "Linux version", so the regexp never matches. There is often no newline at the end of the old log, so if "Linux version" was the first line in the log, it would still not get matched.
Relying on the first line in the log to not change seems likely to cause problems for scripts in the future. Why not separate them where the code knows for sure that the old log is ending and the new log is starting?
Quoted 20 lines
Signed-off-by Anton Vorontsov <[email protected]>---
fs/pstore/ram_core.c | 1 +1 file changed, 1 insertion(+)fs/pstore/ram_core.c +1
-0@@ -406,6 +406,7 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool " size %zu, start %zu\n", buffer_size(prz), buffer_start(prz)); persistent_ram_save_old(prz); + return 0; } } else {pr_info("persistent_ram: no valid data in buffer" --
1.7.9.2
[PATCH/RFC] Make sure linux_banner is the first message in log_buf
For scripting it is important to have a consistent header that tells where the kernel log starts. At least to me it always seemed that linux_banner served this purpose.
Though, an early kernel code may print things before the Linux banner. When we parse logs from multiple boots grabbed from serial or pstore consoles, we might miss these messages.
The only bulletproof, arch-independent and whatnot way to ensure that we have the banner printed first is to print it from the printk itself. The resulting code looks quite obvious.
Sure, this doesn't address bootloader or low-level very early arch- dependent console output that goes to the HW directly, but there's nothing we can do about it (in pstore console we don't see them anyway).
---
Quoted 9 lines · Colin Cross
Quoted 4 lines
Now to get the only most recent messages we can do:
tac ramoops-console | sed '/^Linux version.*(.*@.*)/ q' | tac
Lots of problems with this.
"Linux version ..." is not the first line in the console log on my devices, there are messages before it that shouldn't be dropped by automated logs collectors using this regexp.
Ouch. This seems not right. And the same issue exist if we collect logs from e.g. serial console, there (unlike to just reading /proc/kmsg) we don't know where current kernel's messages start, and more than that, in serial console case we don't know where the messages end (unlike to pstore).
So it's a general problem, not only related to pstore.
But we can fix this. How about the patch below?
Quoted 1 line
There is a timestamp before "Linux version", so the regexp never matches.
This is also fixable.
tac ramoops-console | sed '/\(^\|] \)Linux version.*(.*@.*)/ q' | tac
Quoted 3 lines
There is often no newline at the end of the old log, so if "Linux version" was the first line in the log, it would still not get matched.
Yeah, true. We will have to add at least a new line in pstore.
Quoted 4 lines
Relying on the first line in the log to not change seems likely to cause problems for scripts in the future. Why not separate them where the code knows for sure that the old log is ending and the new log is starting?
I'm not opposed to a header (or a footer) at all, and you're right, one of them is obviously needed.
I just don't like introducing yet another ad-hoc header format that we will only use for pstore/console. We have "start of the Linux kernel log" header, so let's try to use it?..
If it is not suitable for us today, let's think how to fix that, and if anything, we can fall-back to your plan, i.e. adding our own footer (or zapping prz) at boot time.
But so far I can see this solution:
1. Make sure we printk linux_banner as the first string in the log_buf (this patch). This is an improvement not only for pstore;
2. In pstore, add a newline to previous' boot log (we'll add it unconditinally, so that it we won't loose the information about the last new line :-).
init/main.c | 1 - kernel/printk.c | 3 +++ 2 files changed, 3 insertions(+), 1 deletion(-)
init/main.c +0 -1
@@ -492,7 +492,6 @@ asmlinkage void __init start_kernel(void)tick_init ();boot_cpu_init ();page_address_init (); -printk (KERN_NOTICE "%s" , linux_banner);setup_arch (&command_line);mm_init_owner (&init_mm, &init_task);mm_init_cpumask (&init_mm);
kernel/printk.c +3 -0
@@ -749,6 +749,9 @@ asmlinkage int printk(const char *fmt, ...)va_list args;int r; +/* Make sure linux_banner is kernel's first message. */ +printk_once (KERN_NOTICE "%s" , linux_banner); +#ifdef CONFIG_KGDB_KDB if (unlikely (kdb_trap_printk)) {va_start (args, fmt);
Signature · 1 line
1.7.9.2
Re: [PATCH/RFC] Make sure linux_banner is the first message in log_buf
kernel/printk.c asmlinkage int printk(const char *fmt, ...) · line 754
Quoted 7 lines · Anton Vorontsov
kernel/printk.c +3
-0@@ -749,6 +749,9 @@ asmlinkage int printk(const char *fmt, ...) va_list args; int r; + /* Make sure linux_banner is kernel's first message. */ + printk_once(KERN_NOTICE "%s", linux_banner); +
Ugh. No. That is too disgusting for words.
Linus
Re: [PATCH/RFC] Make sure linux_banner is the first message in log_buf
In reply to Anton VorontsovFrom: Anton Vorontsov <[email protected]>
Date: Tue, 22 May 2012 19:35:16 -0700
Quoted 3 lines
For scripting it is important to have a consistent header that tells where the kernel log starts. At least to me it always seemed that
linux_bannerserved this purpose.
Your change will not achieve this goal, many architectures print things long before control passes to init/main.c
Re: [PATCH/RFC] Make sure linux_banner is the first message in log_buf
Quoted 9 lines · David Miller
From: Anton Vorontsov <[email protected]>
Date: Tue, 22 May 2012 19:35:16 -0700Quoted 3 lines
For scripting it is important to have a consistent header that tells where the kernel log starts. At least to me it always seemed that
linux_bannerserved this purpose.Your change will not achieve this goal, many architectures print things long before control passes to
init/main.c
If they use printk, we'll catch these messages, no? It is true that if they just write to the HW directly, the messages are lost for us, and there's nothing we can do about it (and we don't see these messages from the kernel anyway, neither in dmesg, nor in pstore).
So, for serial (or arch-specific) console it is still cumbersome to make proper parsing of all messages, but for pstore/ramconsole it is OK. So, I dunno. I guess I'll have to add a custom header to pstore, heh.
Thanks,
Signature · 2 lines
Anton Vorontsov Email: [email protected]
PATCH v4 4/16 pstore/ram_core: Factor persistent_ram_zap() out of post_init()
In reply to Anton VorontsovA handy function that we will use outside of ram_core soon. But so far just factor it out and start using it in post_init().
--- fs/pstore/ram_core.c | 11 ++++++++--- include/linux/pstore_ram.h | 1 + 2 files changed, 9 insertions(+), 3 deletions(-)
fs/pstore/ram_core.c +8 -3
@@ -320,6 +320,13 @@ void persistent_ram_free_old(struct persistent_ram_zone *prz) prz->old_log_size =0 ; } +void persistent_ram_zap (struct persistent_ram_zone *prz) +{ +atomic_set (&prz->buffer->start,0 ); +atomic_set (&prz->buffer->size,0 ); +persistent_ram_update_header_ecc (prz); +} +static void *persistent_ram_vmap (phys_addr_t start,size_t size) {struct page **pages;
@@ -414,8 +421,7 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool } prz->buffer->sig =PERSISTENT_RAM_SIG ; -atomic_set (&prz->buffer->start,0 ); -atomic_set (&prz->buffer->size,0 ); +persistent_ram_zap (prz);return 0 ; }
@@ -450,7 +456,6 @@ struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start, goto err;persistent_ram_post_init (prz, ecc); -persistent_ram_update_header_ecc (prz);return prz; err:
include/linux/pstore_ram.h +1 -0
@@ -69,6 +69,7 @@ struct persistent_ram_zone * __init persistent_ram_new(phys_addr_t start,size_t size, bool ecc);void persistent_ram_free (struct persistent_ram_zone *prz); +void persistent_ram_zap (struct persistent_ram_zone *prz);struct persistent_ram_zone *persistent_ram_init_ringbuffer (struct device *dev,bool ecc);
Signature · 1 line
1.7.9.2
Re: [PATCH 04/16] pstore/ram_core: Factor persistent_ram_zap() out of post_init()
Quoted 4 lines · Anton Vorontsov
A handy function that we will use outside of
ram_coresoon. But so far just factor it out and start using it inpost_init().Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 5/16 pstore/ram: Should zap persistent zone on unlink
In reply to Anton VorontsovOtherwise, unlinked file will reappear on the next boot.
--- fs/pstore/ram.c | 1 + 1 file changed, 1 insertion(+)
fs/pstore/ram.c +1 -0
@@ -186,6 +186,7 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id,return -EINVAL ;persistent_ram_free_old (cxt->przs[id]); +persistent_ram_zap (cxt->przs[id]);return 0 ; }
Signature · 1 line
1.7.9.2
Re: [PATCH 05/16] pstore/ram: Should zap persistent zone on unlink
Quoted 4 lines · Anton Vorontsov
Otherwise, unlinked file will reappear on the next boot.
Reported-by Kees Cook <[email protected]>Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 6/16 pstore: Add console log messages support
In reply to Anton VorontsovPstore doesn't support logging kernel messages in run-time, it only dumps dmesg when kernel oopses/panics. This makes pstore useless for debugging hangs caused by HW issues or improper use of HW (e.g. weird device inserted -> driver tried to write a reserved bits -> SoC hanged. In that case we don't get any messages in the pstore.
Therefore, let's add a runtime logging support: PSTORE_TYPE_CONSOLE.
--- fs/pstore/Kconfig | 7 +++++++ fs/pstore/inode.c | 3 +++ fs/pstore/platform.c | 33 +++++++++++++++++++++++++++++++++ include/linux/pstore.h | 1 + 4 files changed, 44 insertions(+)
fs/pstore/Kconfig +7 -0
@@ -12,6 +12,13 @@ config PSTORE If you don't have a platform persistent store driver, say N. +config PSTORE_CONSOLE + bool "Log kernel console messages" + depends on PSTORE + help + When the option is enabled, pstore will log all kernel + messages, even if no oops or panic happened. + config PSTORE_RAM tristate "Log panic/oops to a RAM buffer" depends on PSTORE
fs/pstore/inode.c +3 -0
@@ -212,6 +212,9 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,case PSTORE_TYPE_DMESG :sprintf (name,"dmesg-%s-%lld" , psname, id);break ; +case PSTORE_TYPE_CONSOLE : +sprintf (name,"console-%s" , psname); +break ;case PSTORE_TYPE_MCE :sprintf (name,"mce-%s-%lld" , psname, id);break ;
fs/pstore/platform.c +33 -0
@@ -1,6 +1,7 @@/* * Persistent Storage - platform driver interface parts. * +* Copyright (C) 2007-2008 Google, Inc. * Copyright (C) 2010 Intel Corporation <[email protected]> * * This program is free software; you can redistribute it and/or modify
@@ -22,6 +23,7 @@#include <linux/errno.h> #include <linux/init.h> #include <linux/kmsg_dump.h> +#include <linux/console.h> #include <linux/module.h> #include <linux/pstore.h> #include <linux/string.h>
@@ -156,6 +158,36 @@ static struct kmsg_dumper pstore_dumper = { .dump = pstore_dump, }; +#ifdef CONFIG_PSTORE_CONSOLE +static void pstore_console_write (struct console *con,const char *s,unsigned c) +{ +const char *e = s + c; + +while (s < e) { +if (c > psinfo->bufsize) + c = psinfo->bufsize; +memcpy (psinfo->buf, s, c); + psinfo->write (PSTORE_TYPE_CONSOLE ,0 ,NULL ,0 , c, psinfo); + s += c; + c = e - s; + } +} + +static struct console pstore_console = { + .name ="pstore" , + .write = pstore_console_write, + .flags =CON_PRINTBUFFER |CON_ENABLED |CON_ANYTIME , + .index =-1 , +}; + +static void pstore_register_console (void ) +{ +register_console (&pstore_console); +} +#else +static void pstore_register_console (void ) {} +#endif +/* * platform specific persistent storage driver registers with * us here. If pstore is already mounted, call the platform
@@ -193,6 +225,7 @@ int pstore_register(struct pstore_info *psi)pstore_get_records (0 );kmsg_dump_register (&pstore_dumper); +pstore_register_console (); pstore_timer.expires = jiffies +PSTORE_INTERVAL ;add_timer (&pstore_timer);
include/linux/pstore.h +1 -0
@@ -29,6 +29,7 @@enum pstore_type_id {PSTORE_TYPE_DMESG =0 ,PSTORE_TYPE_MCE =1 , +PSTORE_TYPE_CONSOLE =2 ,PSTORE_TYPE_UNKNOWN =255 };
Signature · 1 line
1.7.9.2
PATCH v4 7/16 pstore/ram: Introduce ramoops_context.max_dump_count
In reply to Anton VorontsovSo far it is the same as max_count, but this will change when we'll add support for other message types (e.g. console, mce, tracing).
--- fs/pstore/ram.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
fs/pstore/ram.c +9 -6
@@ -70,6 +70,7 @@ struct ramoops_context {bool ecc;unsigned int count;unsigned int max_count; +unsigned int max_dump_count;unsigned int read_count;struct pstore_info pstore; };
@@ -94,7 +95,7 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,struct ramoops_context *cxt = psi->data;struct persistent_ram_zone *prz; -if (cxt->read_count >= cxt->max_count) +if (cxt->read_count >= cxt->max_dump_count)return -EINVAL ; *id = cxt->read_count++;
@@ -172,7 +173,7 @@ static int ramoops_pstore_write(enum pstore_type_id type, size = prz->buffer_size - hlen;persistent_ram_write (prz, cxt->pstore.buf, size); - cxt->count = (cxt->count +1 ) % cxt->max_count; + cxt->count = (cxt->count +1 ) % cxt->max_dump_count;return 0 ; }
@@ -182,7 +183,7 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, {struct ramoops_context *cxt = psi->data; -if (id >= cxt->max_count) +if (id >= cxt->max_dump_count)return -EINVAL ;persistent_ram_free_old (cxt->przs[id]);
@@ -213,7 +214,7 @@ static int __init ramoops_probe(struct platform_device *pdev)/* Only a single ramoops area allowed at a time, so fail extra * probes. */ -if (cxt->max_count) +if (cxt->max_dump_count) goto fail_out;if (!pdata->mem_size || !pdata->record_size) {
@@ -240,6 +241,7 @@ static int __init ramoops_probe(struct platform_device *pdev) } cxt->max_count = pdata->mem_size / pdata->record_size; + cxt->max_dump_count = cxt->max_count; cxt->count =0 ; cxt->size = pdata->mem_size; cxt->phys_addr = pdata->mem_address;
@@ -247,14 +249,14 @@ static int __init ramoops_probe(struct platform_device *pdev) cxt->dump_oops = pdata->dump_oops; cxt->ecc = pdata->ecc; - cxt->przs =kzalloc (sizeof (*cxt->przs) * cxt->max_count,GFP_KERNEL ); + cxt->przs =kzalloc (sizeof (*cxt->przs) * cxt->max_dump_count,GFP_KERNEL );if (!cxt->przs) { err = -ENOMEM ;dev_err (dev,"failed to initialize a prz array\n" ); goto fail_out; } -for (i =0 ; i < cxt->max_count; i++) { +for (i =0 ; i < cxt->max_dump_count; i++) {size_t sz = cxt->record_size;phys_addr_t start = cxt->phys_addr + sz * i;
@@ -303,6 +305,7 @@ fail_buf: fail_clear: cxt->pstore.bufsize =0 ; cxt->max_count =0 ; + cxt->max_dump_count =0 ; fail_przs:for (i =0 ; cxt->przs[i]; i++)persistent_ram_free (cxt->przs[i]);
Signature · 1 line
1.7.9.2
Re: [PATCH 07/16] pstore/ram: Introduce ramoops_context.max_dump_count
Quoted 5 lines · Anton Vorontsov
So far it is the same as
max_count, but this will change when we'll add support for other message types (e.g. console, mce, tracing).Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 8/16 pstore/ram: Factor dmesg przs initialization out of probe()
In reply to Anton VorontsovThis will help make code clearer when we'll add support for other message types.
This also makes probe() much shorter and understandable, plus makes mem/record size checking a bit easier.
Implementation detail: we now use a paddr pointer, this will be used for allocating persistent ram zones for other message types.
--- fs/pstore/ram.c | 105 ++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 66 insertions(+), 39 deletions(-)
fs/pstore/ram.c +66 -39
@@ -203,13 +203,67 @@ static struct ramoops_context oops_cxt = { }, }; +static void ramoops_free_przs (struct ramoops_context *cxt) +{ +int i; + +if (!cxt->przs) +return ; + +for (i =0 ; cxt->przs[i]; i++) +persistent_ram_free (cxt->przs[i]); +kfree (cxt->przs); +} + +static int ramoops_init_przs (struct device *dev,struct ramoops_context *cxt, +phys_addr_t *paddr,size_t dump_mem_sz) +{ +int err = -ENOMEM ; +int i; + +if (!cxt->record_size) +return 0 ; + + cxt->max_dump_count = dump_mem_sz / cxt->record_size; +if (!cxt->max_dump_count) +return -ENOMEM ; + + cxt->przs =kzalloc (sizeof (*cxt->przs) * cxt->max_dump_count, +GFP_KERNEL ); +if (!cxt->przs) { +dev_err (dev,"failed to initialize a prz array for dumps\n" ); +return -ENOMEM ; + } + +for (i =0 ; i < cxt->max_dump_count; i++) { +size_t sz = cxt->record_size; + + cxt->przs[i] =persistent_ram_new (*paddr, sz, cxt->ecc); +if (IS_ERR (cxt->przs[i])) { + err =PTR_ERR (cxt->przs[i]); +dev_err (dev,"failed to request mem region (0x%zx@0x%llx): %d\n" , + sz, (unsigned long long )*paddr, err); + goto fail_prz; + } + *paddr += sz; + } + + cxt->max_count += cxt->max_dump_count; + +return 0 ; +fail_prz: +ramoops_free_przs (cxt); +return err; +} +static int __init ramoops_probe (struct platform_device *pdev) {struct device *dev = &pdev->dev;struct ramoops_platform_data *pdata = pdev->dev.platform_data;struct ramoops_context *cxt = &oops_cxt; +size_t dump_mem_sz; +phys_addr_t paddr;int err = -EINVAL ; -int i;/* Only a single ramoops area allowed at a time, so fail extra * probes.
@@ -226,22 +280,7 @@ static int __init ramoops_probe(struct platform_device *pdev) pdata->mem_size =rounddown_pow_of_two (pdata->mem_size); pdata->record_size =rounddown_pow_of_two (pdata->record_size); -/* Check for the minimum memory size */ -if (pdata->mem_size <MIN_MEM_SIZE && - pdata->record_size <MIN_MEM_SIZE ) { -pr_err ("memory size too small, minimum is %lu\n" , -MIN_MEM_SIZE ); - goto fail_out; - } - -if (pdata->mem_size < pdata->record_size) { -pr_err ("The memory size must be larger than the " -"records size\n" ); - goto fail_out; - } - - cxt->max_count = pdata->mem_size / pdata->record_size; - cxt->max_dump_count = cxt->max_count; + cxt->max_count =0 ; cxt->count =0 ; cxt->size = pdata->mem_size; cxt->phys_addr = pdata->mem_address;
@@ -249,24 +288,14 @@ static int __init ramoops_probe(struct platform_device *pdev) cxt->dump_oops = pdata->dump_oops; cxt->ecc = pdata->ecc; - cxt->przs =kzalloc (sizeof (*cxt->przs) * cxt->max_dump_count,GFP_KERNEL ); -if (!cxt->przs) { - err = -ENOMEM ; -dev_err (dev,"failed to initialize a prz array\n" ); - goto fail_out; - } - -for (i =0 ; i < cxt->max_dump_count; i++) { -size_t sz = cxt->record_size; -phys_addr_t start = cxt->phys_addr + sz * i; + paddr = cxt->phys_addr; - cxt->przs[i] =persistent_ram_new (start, sz, cxt->ecc); -if (IS_ERR (cxt->przs[i])) { - err =PTR_ERR (cxt->przs[i]); -dev_err (dev,"failed to request mem region (0x%zx@0x%llx): %d\n" , - sz, (unsigned long long )start, err); - goto fail_przs; - } + dump_mem_sz = cxt->size; + err =ramoops_init_przs (dev, cxt, &paddr, dump_mem_sz); +if (err) { +pr_err ("memory size too small, minimum is %lu\n" , + cxt->record_size); + goto fail_count; } cxt->pstore.data = cxt;
@@ -279,7 +308,7 @@ static int __init ramoops_probe(struct platform_device *pdev) } err =pstore_register (&cxt->pstore); -if (err) { +if (err || !cxt->max_count) {pr_err ("registering with pstore failed\n" ); goto fail_buf; }
@@ -306,10 +335,8 @@ fail_clear: cxt->pstore.bufsize =0 ; cxt->max_count =0 ; cxt->max_dump_count =0 ; -fail_przs: -for (i =0 ; cxt->przs[i]; i++) -persistent_ram_free (cxt->przs[i]); -kfree (cxt->przs); +fail_count: +ramoops_free_przs (cxt); fail_out:return err; }
Signature · 1 line
1.7.9.2
Re: [PATCH 08/16] pstore/ram: Factor dmesg przs initialization out of probe()
Quoted 11 lines · Anton Vorontsov
This will help make code clearer when we'll add support for other message types.
This also makes
probe()much shorter and understandable, plus makes mem/record size checking a bit easier.Implementation detail: we now use a paddr pointer, this will be used for allocating persistent ram zones for other message types.
Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 9/16 pstore/ram: Factor ramoops_get_dump_prz() out of ramoops_pstore_read()
In reply to Anton VorontsovThis will help make code clearer when we'll add support for other message types.
The patch also changes return value from -EINVAL to 0 in case of end-of-records. The exact value doesn't matter for pstore (it should be just <= 0), but 0 feels more correct.
--- fs/pstore/ram.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-)
fs/pstore/ram.c +22 -6
@@ -86,6 +86,24 @@ static int ramoops_pstore_open(struct pstore_info *psi)return 0 ; } +static struct persistent_ram_zone * +ramoops_get_dump_prz (u64 id,enum pstore_type_id *type, +struct ramoops_context *cxt) +{ +struct persistent_ram_zone *prz; + +if (id > cxt->max_dump_count) +return NULL ; + + prz = cxt->przs[id]; +if (!persistent_ram_old_size (prz)) +return NULL ; + + *type =PSTORE_TYPE_DMESG ; + +return prz; +} + static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, struct timespec *time, char **buf,
@@ -95,14 +113,12 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,struct ramoops_context *cxt = psi->data;struct persistent_ram_zone *prz; -if (cxt->read_count >= cxt->max_dump_count) -return -EINVAL ; - *id = cxt->read_count++; - prz = cxt->przs[*id]; -/* Only supports dmesg output so far. */ - *type =PSTORE_TYPE_DMESG ; + prz =ramoops_get_dump_prz (*id, type, cxt); +if (!prz) +return 0 ; +/* TODO(kees): Bogus time for the moment. */ time->tv_sec =0 ; time->tv_nsec =0 ;
Signature · 1 line
1.7.9.2
Re: [PATCH 09/16] pstore/ram: Factor ramoops_get_dump_prz() out of ramoops_pstore_read()
Quoted 8 lines · Anton Vorontsov
This will help make code clearer when we'll add support for other message types.
The patch also changes return value from
-EINVALto 0 in case of end-of-records. The exact value doesn't matter for pstore (it should be just <= 0), but 0 feels more correct.Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 10/16 pstore/ram: Add console messages handling
In reply to Anton VorontsovThe console log size is configurable via ramoops.console_size module option, and the log itself is available via <pstore-mount>/console-ramoops file.
--- fs/pstore/ram.c | 107 ++++++++++++++++++++++++++++++++++++++------ include/linux/pstore_ram.h | 1 + 2 files changed, 95 insertions(+), 13 deletions(-)
fs/pstore/ram.c +94 -13
@@ -41,6 +41,10 @@ module_param(record_size, ulong, 0400);MODULE_PARM_DESC (record_size,"size of each dump done on oops/panic" ); +static ulong ramoops_console_size =MIN_MEM_SIZE ; +module_param_named (console_size, ramoops_console_size, ulong,0400 ); +MODULE_PARM_DESC (console_size,"size of kernel console log" ); +static ulong mem_address;module_param (mem_address, ulong,0400 ); MODULE_PARM_DESC(mem_address,
@@ -63,9 +67,11 @@ MODULE_PARM_DESC(ramoops_ecc,struct ramoops_context {struct persistent_ram_zone **przs; +struct persistent_ram_zone *cprz;phys_addr_t phys_addr;unsigned long size;size_t record_size; +size_t console_size;int dump_oops;bool ecc;unsigned int count;
@@ -96,6 +102,9 @@ ramoops_get_dump_prz(u64 id, enum pstore_type_id *type,return NULL ; prz = cxt->przs[id]; + +/* Update old/shadowed buffer. */ +persistent_ram_save_old (prz);if (!persistent_ram_old_size (prz))return NULL ;
@@ -104,6 +113,19 @@ ramoops_get_dump_prz(u64 id, enum pstore_type_id *type,return prz; } +static struct persistent_ram_zone * +ramoops_get_console_prz (u64 id,enum pstore_type_id *type, +struct ramoops_context *cxt) +{ +if (id >= cxt->max_count) +return NULL ; + + *type =PSTORE_TYPE_CONSOLE ; + cxt->read_count = cxt->max_count; + +return cxt->cprz; +} + static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, struct timespec *time, char **buf,
@@ -117,14 +139,14 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, prz =ramoops_get_dump_prz (*id, type, cxt);if (!prz) + prz =ramoops_get_console_prz (*id, type, cxt); +if (!prz)return 0 ;/* TODO(kees): Bogus time for the moment. */ time->tv_sec =0 ; time->tv_nsec =0 ; -/* Update old/shadowed buffer. */ -persistent_ram_save_old (prz); size =persistent_ram_old_size (prz); *buf =kmalloc (size,GFP_KERNEL );if (*buf ==NULL )
@@ -161,7 +183,13 @@ static int ramoops_pstore_write(enum pstore_type_id type,struct persistent_ram_zone *prz = cxt->przs[cxt->count];size_t hlen; -/* Currently ramoops is designed to only store dmesg dumps. */ +if (type ==PSTORE_TYPE_CONSOLE ) { +if (!cxt->cprz) +return -ENOMEM ; +persistent_ram_write (cxt->cprz, cxt->pstore.buf, size); +return 0 ; + } +if (type !=PSTORE_TYPE_DMESG )return -EINVAL ;
@@ -198,12 +226,17 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, struct pstore_info *psi) {struct ramoops_context *cxt = psi->data; +struct persistent_ram_zone *prz; -if (id >= cxt->max_dump_count) +if (id >= cxt->max_dump_count && id < cxt->max_count) + prz = cxt->cprz; +else if (id < cxt->max_dump_count) + prz = cxt->przs[id]; +else return -EINVAL ; -persistent_ram_free_old (cxt->przs[id]); -persistent_ram_zap (cxt->przs[id]); +persistent_ram_free_old (prz); +persistent_ram_zap (prz);return 0 ; }
@@ -272,6 +305,35 @@ fail_prz:return err; } +static void ramoops_free_cprz (struct ramoops_context *cxt) +{ +kfree (cxt->cprz); +} + +static int ramoops_init_cprz (struct device *dev,struct ramoops_context *cxt, +phys_addr_t *paddr,size_t console_mem_sz) +{ +if (!console_mem_sz) +return 0 ; + +if (*paddr + console_mem_sz > *paddr + cxt->size) +return -ENOMEM ; + + cxt->cprz =persistent_ram_new (*paddr, console_mem_sz, cxt->ecc); +if (IS_ERR (cxt->cprz)) { +int err =PTR_ERR (cxt->cprz); + +dev_err (dev,"failed to request mem region (0x%zx@0x%llx): %d\n" , + console_mem_sz, (unsigned long long )*paddr, err); +return err; + } + + *paddr += console_mem_sz; + cxt->max_count++; + +return 0 ; +} +static int __init ramoops_probe (struct platform_device *pdev) {struct device *dev = &pdev->dev;
@@ -287,35 +349,51 @@ static int __init ramoops_probe(struct platform_device *pdev)if (cxt->max_dump_count) goto fail_out; -if (!pdata->mem_size || !pdata->record_size) { -pr_err ("The memory size and the record size must be " +if (!pdata->mem_size || (!pdata->record_size && !pdata->console_size)) { +pr_err ("The memory size and the record/console size must be " "non-zero\n" ); goto fail_out; } pdata->mem_size =rounddown_pow_of_two (pdata->mem_size); pdata->record_size =rounddown_pow_of_two (pdata->record_size); + pdata->console_size =rounddown_pow_of_two (pdata->console_size); cxt->max_count =0 ; cxt->count =0 ; cxt->size = pdata->mem_size; cxt->phys_addr = pdata->mem_address; cxt->record_size = pdata->record_size; + cxt->console_size = pdata->console_size; cxt->dump_oops = pdata->dump_oops; cxt->ecc = pdata->ecc; paddr = cxt->phys_addr; - dump_mem_sz = cxt->size; + dump_mem_sz = cxt->size - cxt->console_size; err =ramoops_init_przs (dev, cxt, &paddr, dump_mem_sz); -if (err) { +if (err) + goto fail_out; + + err =ramoops_init_cprz (dev, cxt, &paddr, cxt->console_size); +if (err) + goto fail_init_cprz; + +if (!cxt->max_count) {pr_err ("memory size too small, minimum is %lu\n" , - cxt->record_size); + cxt->console_size + cxt->record_size); goto fail_count; } cxt->pstore.data = cxt; - cxt->pstore.bufsize = cxt->przs[0 ]->buffer_size; +/* +* Console can handle any buffer size, so prefer dumps buffer +* size since usually it is smaller. +*/ +if (cxt->przs) + cxt->pstore.bufsize = cxt->przs[0 ]->buffer_size; +else + cxt->pstore.bufsize = cxt->cprz->buffer_size; cxt->pstore.buf =kmalloc (cxt->pstore.bufsize,GFP_KERNEL );spin_lock_init (&cxt->pstore.buf_lock);if (!cxt->pstore.buf) {
@@ -324,7 +402,7 @@ static int __init ramoops_probe(struct platform_device *pdev) } err =pstore_register (&cxt->pstore); -if (err || !cxt->max_count) { +if (err) {pr_err ("registering with pstore failed\n" ); goto fail_buf; }
@@ -352,6 +430,8 @@ fail_clear: cxt->max_count =0 ; cxt->max_dump_count =0 ; fail_count: +ramoops_free_cprz (cxt); +fail_init_cprz:ramoops_free_przs (cxt); fail_out:return err;
@@ -403,6 +483,7 @@ static int __init ramoops_init(void) dummy_data->mem_size = mem_size; dummy_data->mem_address = mem_address; dummy_data->record_size = record_size; + dummy_data->console_size = ramoops_console_size; dummy_data->dump_oops = dump_oops; dummy_data->ecc = ramoops_ecc; dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
include/linux/pstore_ram.h +1 -0
@@ -93,6 +93,7 @@ struct ramoops_platform_data {unsigned long mem_size;unsigned long mem_address;unsigned long record_size; +unsigned long console_size;int dump_oops;bool ecc; };
Signature · 1 line
1.7.9.2
Re: [PATCH 10/16] pstore/ram: Add console messages handling
Quoted 5 lines · Anton Vorontsov
The console log size is configurable via ramoops.console_size module option, and the log itself is available via <pstore-mount>/console-ramoops file.
Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 11/16 pstore/ram_core: Silence some printks
In reply to Anton VorontsovSince we use multiple regions, the messages are somewhat annoying. We do print total mapped memory already, so no need to print the information for each region in the library routines.
--- fs/pstore/ram_core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
fs/pstore/ram_core.c +2 -2
@@ -409,14 +409,14 @@ static int __init persistent_ram_post_init(struct persistent_ram_zone *prz, bool" size %zu, start %zu\n" , buffer_size(prz), buffer_start(prz)); else { -pr_info ("persistent_ram: found existing buffer," +pr_debug ("persistent_ram: found existing buffer," " size %zu, start %zu\n" ,buffer_size (prz),buffer_start (prz));persistent_ram_save_old (prz);return 0 ; } }else { -pr_info ("persistent_ram: no valid data in buffer" +pr_debug ("persistent_ram: no valid data in buffer" " (sig = 0x%08x)\n" , prz->buffer->sig); }
Signature · 1 line
1.7.9.2
PATCH v4 12/16 pstore/ram: Add some more documentation and examples
In reply to Anton Vorontsov--- Documentation/ramoops.txt | 14 ++++++++++++++ 1 file changed, 14 insertions(+)
Documentation/ramoops.txt +14 -0
@@ -40,6 +40,12 @@ corrupt, but usually it is restorable. Setting the ramoops parameters can be done in 2 different manners: 1. Use the module parameters (which have the names of the variables described as before). + For quick debugging, you can also reserve parts of memory during boot + and then use the reserved memory for ramoops. For example, assuming a machine + with > 128 MB of memory, the following kernel command line will tell the + kernel to use only the first 128 MB of memory, and place ECC-protected ramoops + region at 128 MB boundary: + "mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1" 2. Use a platform device and set the platform data. The parameters can then be set through that platform data. An example of doing that is:
@@ -70,6 +76,14 @@ if (ret) { return ret; } +You can specify either RAM memory or peripheral devices' memory. However, when +specifying RAM, be sure to reserve the memory by issuing memblock_reserve() +very early in the architecture code, e.g.: + +#include <linux/memblock.h> + +memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size); + 3. Dump format The data dump begins with a header, currently defined as "====" followed by a
Signature · 1 line
1.7.9.2
PATCH v4 13/16 staging/android: Remove ram_console driver
In reply to Anton VorontsovAll the functionality is now supported by pstore and pstore_ram drivers.
--- drivers/staging/android/Kconfig | 5 - drivers/staging/android/Makefile | 1 - drivers/staging/android/ram_console.c | 179 --------------------------------- 3 files changed, 185 deletions(-) delete mode 100644 drivers/staging/android/ram_console.c
drivers/staging/android/Kconfig +0 -5
@@ -25,11 +25,6 @@ config ANDROID_LOGGER tristate "Android log driver" default n -config ANDROID_RAM_CONSOLE - bool "Android RAM buffer console" - depends on !S390 && !UML && HAVE_MEMBLOCK && PSTORE_RAM=y - default n - config ANDROID_TIMED_OUTPUT bool "Timed output class driver" default y
drivers/staging/android/Makefile +0 -1
@@ -1,7 +1,6 @@ obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o obj-$(CONFIG_ASHMEM) += ashmem.o obj-$(CONFIG_ANDROID_LOGGER) += logger.o -obj-$(CONFIG_ANDROID_RAM_CONSOLE) += ram_console.o obj-$(CONFIG_ANDROID_TIMED_OUTPUT) += timed_output.o obj-$(CONFIG_ANDROID_TIMED_GPIO) += timed_gpio.o obj-$(CONFIG_ANDROID_LOW_MEMORY_KILLER) += lowmemorykiller.o
drivers/staging/android/ram_console.c deleted +0 -179
179 lines not on this page · raw message
Signature · 1 line
1.7.9.2
PATCH v4 14/16 pstore/ram_core: Remove now unused code
In reply to Anton VorontsovThe code tried to maintain the global list of persistent ram zones, which isn't a great idea overall, plus since Android's ram_console is no longer there, we can remove some unused functions.
--- fs/pstore/ram_core.c | 77 -------------------------------------------- include/linux/pstore_ram.h | 19 ----------- 2 files changed, 96 deletions(-)
fs/pstore/ram_core.c +0 -77
@@ -35,8 +35,6 @@ struct persistent_ram_buffer {#define PERSISTENT_RAM_SIG (0x43474244)/* DBGC */ -static __initdata LIST_HEAD (persistent_ram_list); -static inline size_t buffer_size (struct persistent_ram_zone *prz) {return atomic_read (&prz->buffer->size);
@@ -462,78 +460,3 @@ err:kfree (prz);return ERR_PTR (ret); } - -#ifndef MODULE -static int __init persistent_ram_buffer_init (const char *name, -struct persistent_ram_zone *prz) -{ -int i; -struct persistent_ram *ram; -struct persistent_ram_descriptor *desc; -phys_addr_t start; - -list_for_each_entry (ram, &persistent_ram_list, node) { - start = ram->start; -for (i =0 ; i < ram->num_descs; i++) { - desc = &ram->descs[i]; -if (!strcmp (desc->name, name)) -return persistent_ram_buffer_map (start, - desc->size, prz); - start += desc->size; - } - } - -return -EINVAL ; -} - -static __init -struct persistent_ram_zone *__persistent_ram_init (struct device *dev,bool ecc) -{ -struct persistent_ram_zone *prz; -int ret = -ENOMEM ; - - prz =kzalloc (sizeof (struct persistent_ram_zone ),GFP_KERNEL ); -if (!prz) { -pr_err ("persistent_ram: failed to allocate persistent ram zone\n" ); - goto err; - } - - ret =persistent_ram_buffer_init (dev_name (dev), prz); -if (ret) { -pr_err ("persistent_ram: failed to initialize buffer\n" ); - goto err; - } - -persistent_ram_post_init (prz, ecc); - -return prz; -err: -kfree (prz); -return ERR_PTR (ret); -} - -struct persistent_ram_zone *__init -persistent_ram_init_ringbuffer (struct device *dev,bool ecc) -{ -return __persistent_ram_init (dev, ecc); -} - -int __init persistent_ram_early_init (struct persistent_ram *ram) -{ -int ret; - - ret =memblock_reserve (ram->start, ram->size); -if (ret) { -pr_err ("Failed to reserve persistent memory from %08lx-%08lx\n" , - (long )ram->start, (long )(ram->start + ram->size -1 )); -return ret; - } - -list_add_tail (&ram->node, &persistent_ram_list); - -pr_info ("Initialized persistent memory from %08lx-%08lx\n" , - (long )ram->start, (long )(ram->start + ram->size -1 )); - -return 0 ; -} -#endif
include/linux/pstore_ram.h +0 -19
@@ -25,21 +25,6 @@struct persistent_ram_buffer ; -struct persistent_ram_descriptor { -const char *name; -phys_addr_t size; -}; - -struct persistent_ram { -phys_addr_t start; -phys_addr_t size; - -int num_descs; -struct persistent_ram_descriptor *descs; - -struct list_head node; -}; -struct persistent_ram_zone {phys_addr_t paddr;size_t size;
@@ -63,15 +48,11 @@ struct persistent_ram_zone {size_t old_log_size; }; -int persistent_ram_early_init (struct persistent_ram *ram); -struct persistent_ram_zone *__init persistent_ram_new (phys_addr_t start,size_t size,bool ecc);void persistent_ram_free (struct persistent_ram_zone *prz);void persistent_ram_zap (struct persistent_ram_zone *prz); -struct persistent_ram_zone *persistent_ram_init_ringbuffer (struct device *dev, -bool ecc);int persistent_ram_write (struct persistent_ram_zone *prz,const void *s,unsigned int count);
Signature · 1 line
1.7.9.2
PATCH v4 15/16 pstore/platform: Make automatic updates interval configurable
In reply to Anton VorontsovThere is no behavioural change, the default value is still 60 seconds.
--- fs/pstore/platform.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
fs/pstore/platform.c +11 -4
@@ -31,6 +31,7 @@#include <linux/slab.h> #include <linux/uaccess.h> #include <linux/hardirq.h> +#include <linux/jiffies.h> #include <linux/workqueue.h> #include "internal.h"
@@ -40,7 +41,10 @@* whether the system is actually still running well enough * to let someone see the entry */ -#define PSTORE_INTERVAL (60 * HZ) +static int pstore_update_ms =60000 ; +module_param_named (update_ms, pstore_update_ms, int,0600 ); +MODULE_PARM_DESC (update_ms,"milliseconds before pstore updates its content " +"(default is 60000; -1 means runtime updates are disabled)" );static int pstore_new_entry;
@@ -227,8 +231,11 @@ int pstore_register(struct pstore_info *psi)kmsg_dump_register (&pstore_dumper);pstore_register_console (); - pstore_timer.expires = jiffies +PSTORE_INTERVAL ; -add_timer (&pstore_timer); +if (pstore_update_ms >=0 ) { + pstore_timer.expires = jiffies + +msecs_to_jiffies (pstore_update_ms); +add_timer (&pstore_timer); + }return 0 ; }
@@ -287,7 +294,7 @@ static void pstore_timefunc(unsigned long dummy)schedule_work (&pstore_work); } -mod_timer (&pstore_timer, jiffies +PSTORE_INTERVAL ); +mod_timer (&pstore_timer, jiffies +msecs_to_jiffies (pstore_update_ms)); }module_param (backend, charp,0444 );
Signature · 1 line
1.7.9.2
Re: [PATCH 15/16] pstore/platform: Make automatic updates interval configurable
Quoted 3 lines · Anton Vorontsov
There is no behavioural change, the default value is still 60 seconds.
Signed-off-by Anton Vorontsov <[email protected]>
Signature · 2 lines
Kees Cook Chrome OS Security
PATCH v4 16/16 pstore/platform: Disable automatic updates by default
In reply to Anton VorontsovHaving automatic updates seems pointless for production system, and even dangerous and thus counter-productive:
1. If we can mount pstore, or read files, we can as well read /proc/kmsg. So, there's little point in duplicating the functionality and present the same information but via another userland ABI;
2. Expecting the kernel to behave sanely after oops/panic is naive. It might work, but you'd rather not try it. Screwed up kernel can do rather bad things, like recursive faults[1]; and pstore rather provoking bad things to happen. It uses:
1. Timers (assumes sane interrupts state);
2. Workqueues and mutexes (assumes scheduler in a sane state);
3. kzalloc (a working slab allocator);
That's too much for a dead kernel, so the debugging facility itself might just make debugging harder, which is not what we want.
Maybe for non-oops message types it would make sense to re-enable automatic updates, but so far I don't see any use case for this. Even for tracing, it has its own run-time/normal ABI, so we're only interested in pstore upon next boot, to retrieve what has gone wrong with HW or SW.
So, let's disable the updates by default.
[1]
BUG: unable to handle kernel paging request at fffffffffffffff8 IP: [<ffffffff8104801b>] kthread_data+0xb/0x20 [...] Process kworker/0:1 (pid: 14, threadinfo ffff8800072c0000, task ffff88000725b100) [... Call Trace: [<ffffffff81043710>] wq_worker_sleeping+0x10/0xa0 [<ffffffff813687a8>] __schedule+0x568/0x7d0 [<ffffffff8106c24d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff81087e22>] ? call_rcu_sched+0x12/0x20 [<ffffffff8102b596>] ? release_task+0x156/0x2d0 [<ffffffff8102b45e>] ? release_task+0x1e/0x2d0 [<ffffffff8106c24d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff81368ac4>] schedule+0x24/0x70 [<ffffffff8102cba8>] do_exit+0x1f8/0x370 [<ffffffff810051e7>] oops_end+0x77/0xb0 [<ffffffff8135c301>] no_context+0x1a6/0x1b5 [<ffffffff8135c4de>] __bad_area_nosemaphore+0x1ce/0x1ed [<ffffffff81053156>] ? ttwu_queue+0xc6/0xe0 [<ffffffff8135c50b>] bad_area_nosemaphore+0xe/0x10 [<ffffffff8101fa47>] do_page_fault+0x2c7/0x450 [<ffffffff8106e34b>] ? __lock_release+0x6b/0xe0 [<ffffffff8106bf21>] ? mark_held_locks+0x61/0x140 [<ffffffff810502fe>] ? __wake_up+0x4e/0x70 [<ffffffff81185f7d>] ? trace_hardirqs_off_thunk+0x3a/0x3c [<ffffffff81158970>] ? pstore_register+0x120/0x120 [<ffffffff8136a37f>] page_fault+0x1f/0x30 [<ffffffff81158970>] ? pstore_register+0x120/0x120 [<ffffffff81185ab8>] ? memcpy+0x68/0x110 [<ffffffff8115875a>] ? pstore_get_records+0x3a/0x130 [<ffffffff811590f4>] ? persistent_ram_copy_old+0x64/0x90 [<ffffffff81158bf4>] ramoops_pstore_read+0x84/0x130 [<ffffffff81158799>] pstore_get_records+0x79/0x130 [<ffffffff81042536>] ? process_one_work+0x116/0x450 [<ffffffff81158970>] ? pstore_register+0x120/0x120 [<ffffffff8115897e>] pstore_dowork+0xe/0x10 [<ffffffff81042594>] process_one_work+0x174/0x450 [<ffffffff81042536>] ? process_one_work+0x116/0x450 [<ffffffff81042e13>] worker_thread+0x123/0x2d0 [<ffffffff81042cf0>] ? manage_workers.isra.28+0x120/0x120 [<ffffffff81047d8e>] kthread+0x8e/0xa0 [<ffffffff8136ba74>] kernel_thread_helper+0x4/0x10 [<ffffffff8136a199>] ? retint_restore_args+0xe/0xe [<ffffffff81047d00>] ? __init_kthread_worker+0x70/0x70 [<ffffffff8136ba70>] ? gs_change+0xb/0xb Code: be e2 00 00 00 48 c7 c7 d1 2a 4e 81 e8 bf fb fd ff 48 8b 5d f0 4c 8b 65 f8 c9 c3 0f 1f 44 00 00 48 8b 87 08 02 00 00 55 48 89 e5 <48> 8b 40 f8 5d c3 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 RIP [<ffffffff8104801b>] kthread_data+0xb/0x20 RSP <ffff8800072c1888> CR2: fffffffffffffff8 ---[ end trace 996a332dc399111d ]---
Fixing recursive fault but reboot is needed!
--- fs/pstore/platform.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
fs/pstore/platform.c +3 -2
@@ -41,10 +41,11 @@* whether the system is actually still running well enough * to let someone see the entry */ -static int pstore_update_ms =60000 ; +static int pstore_update_ms =-1 ;module_param_named (update_ms, pstore_update_ms, int,0600 );MODULE_PARM_DESC (update_ms,"milliseconds before pstore updates its content " -"(default is 60000; -1 means runtime updates are disabled)" ); +"(default is -1, which means runtime updates are disabled; " +"enabling this option is not safe)" );static int pstore_new_entry;
Signature · 1 line
1.7.9.2
Re: [PATCH 16/16] pstore/platform: Disable automatic updates by default
Quoted 21 lines · Anton Vorontsov
Having automatic updates seems pointless for production system, and even dangerous and thus counter-productive:
1. If we can mount pstore, or read files, we can as well read
/proc/kmsg. So, there's little point in duplicating the functionality and present the same information but via another userland ABI;2. Expecting the kernel to behave sanely after oops/panic is naive. It might work, but you'd rather not try it. Screwed up kernel can do rather bad things, like recursive faults[1]; and pstore rather provoking bad things to happen. It uses:
1. Timers (assumes sane interrupts state);
2. Workqueues and mutexes (assumes scheduler in a sane state);
3. kzalloc (a working slab allocator);That's too much for a dead kernel, so the debugging facility itself might just make debugging harder, which is not what we want.
Quoted 7 lines
Maybe for non-oops message types it would make sense to re-enable automatic updates, but so far I don't see any use case for this. Even for tracing, it has its own run-time/normal ABI, so we're only interested in pstore upon next boot, to retrieve what has gone wrong with HW or SW.
So, let's disable the updates by default.
I'll let Tony ack this, but I'm fine with it -- making this configurable is sufficient for my needs. :)
Quoted 11 lines
fs/pstore/platform.c +1
-1@@ -41,10 +41,11 @@* whether the system is actually still running well enough * to let someone see the entry */ -static int pstore_update_ms =60000 ; +static int pstore_update_ms =-1 ; module_param_named(update_ms, pstore_update_ms, int, 0600);
Quoted 4 lines
MODULE_PARM_DESC(update_ms, "milliseconds before pstore updates its content "
- "(default is 60000; -1 means runtime updates are disabled)");
+ "(default is -1, which means runtime updates are disabled; "
+ "enabling this option is not safe)");
Perhaps "enabling this option may lead to further corruption on Oopses" or something more specific?
-Kees
Signature · 2 lines
Kees Cook Chrome OS Security
Greg Kroah-Hartman
maintainerQuoted 10 lines · Anton Vorontsov
Hi all,
A brand new v4:
- Per Kees Cook's comments, the patches no longer remove an automatic updates feature, but instead make the it configurable; plus disable it by default (in a separate patch);
- Fixed some bugs noticed by Colin Cross;
- Documented new continuous ramoops-console log behaviour (also noticed by Colin Cross).
In case you were wondering, all of this is going to have to wait for 3.6, as the 3.5 merge window with my trees have been closed. I'll be able to start accepting patches once 3.5-rc1 is out, so take your time in getting this all working properly, there's no rush here.
greg k-h
Quoted 12 lines · Greg Kroah-Hartman
Quoted 10 lines · Anton Vorontsov
Hi all,
A brand new v4:
- Per Kees Cook's comments, the patches no longer remove an automatic updates feature, but instead make the it configurable; plus disable it by default (in a separate patch);
- Fixed some bugs noticed by Colin Cross;
- Documented new continuous ramoops-console log behaviour (also noticed by Colin Cross).
Quoted 4 lines
In case you were wondering, all of this is going to have to wait for 3.6, as the 3.5 merge window with my trees have been closed. I'll be able to start accepting patches once 3.5-rc1 is out, so take your time in getting this all working properly, there's no rush here.
Will the ramoops stuff that was in -next (via -mm) that now landed in -staging make it sanely into 3.5? Specifically the two patches at the top of:
http://git.kernel.org/?p=linux/kernel/git/kees/linux.git;a=shortlog;h=refs/heads/ramoops
Thanks,
-Kees
Signature · 2 lines
Kees Cook Chrome OS Security
Greg Kroah-Hartman
maintainerQuoted 19 lines · Kees Cook
Quoted 12 lines · Greg Kroah-Hartman
Quoted 10 lines · Anton Vorontsov
Hi all,
A brand new v4:
- Per Kees Cook's comments, the patches no longer remove an automatic updates feature, but instead make the it configurable; plus disable it by default (in a separate patch);
- Fixed some bugs noticed by Colin Cross;
- Documented new continuous ramoops-console log behaviour (also noticed by Colin Cross).Quoted 4 lines
In case you were wondering, all of this is going to have to wait for 3.6, as the 3.5 merge window with my trees have been closed. I'll be able to start accepting patches once 3.5-rc1 is out, so take your time in getting this all working properly, there's no rush here.
Quoted 4 lines
Will the ramoops stuff that was in -next (via -mm) that now landed in -staging make it sanely into 3.5? Specifically the two patches at the top of:
http://git.kernel.org/?p=linux/kernel/git/kees/linux.git;a=shortlog;h=refs/heads/ramoops
Anything that was in staging and linux-next already, yes, will go in for 3.5, I've already sent Linus the pull request for that.
Is that a problem?
thanks,
greg k-h
Quoted 25 lines · Greg Kroah-Hartman
Quoted 19 lines · Kees Cook
Quoted 12 lines · Greg Kroah-Hartman
Quoted 10 lines · Anton Vorontsov
Hi all,
A brand new v4:
- Per Kees Cook's comments, the patches no longer remove an automatic updates feature, but instead make the it configurable; plus disable it by default (in a separate patch);
- Fixed some bugs noticed by Colin Cross;
- Documented new continuous ramoops-console log behaviour (also noticed by Colin Cross).Quoted 4 lines
In case you were wondering, all of this is going to have to wait for 3.6, as the 3.5 merge window with my trees have been closed. I'll be able to start accepting patches once 3.5-rc1 is out, so take your time in getting this all working properly, there's no rush here.
Quoted 4 lines
Will the ramoops stuff that was in -next (via -mm) that now landed in -staging make it sanely into 3.5? Specifically the two patches at the top of:
http://git.kernel.org/?p=linux/kernel/git/kees/linux.git;a=shortlog;h=refs/heads/ramoops
Quoted 4 lines
Anything that was in staging and linux-next already, yes, will go in for 3.5, I've already sent Linus the pull request for that.
Is that a problem?
No problem at all -- it missed 3.4 on a technicality, and I didn't want it to miss 3.5 too. :)
Thanks!
-Kees
Signature · 2 lines
Kees Cook Chrome OS Security