pstore: Change kmsg_bytes storage size to u32
Kees Cook
maintainerPATCH 1/1 pstore: Change kmsg_bytes storage size to u32
The types around kmsg_bytes were inconsistent. The global was unsigned long, the argument to pstore_set_kmsg_bytes() was int, and the filesystem option was u32. Given other internal limits, there's not much sense in making a single pstore record larger than INT_MAX and it can't be negative, so use u32 everywhere. Additionally, use READ/WRITE_ONCE and a local variable in pstore_dump() to avoid kmsg_bytes changing during a dump.
Signed-off-by Kees Cook <[email protected]>
---
Cc: Eric Sandeen <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: "Guilherme G. Piccoli" <[email protected]>
Cc: [email protected]
--- fs/pstore/inode.c | 2 +- fs/pstore/internal.h | 4 ++-- fs/pstore/platform.c | 11 ++++++----- 3 files changed, 9 insertions(+), 8 deletions(-)
fs/pstore/inode.c +1 -1
@@ -265,7 +265,7 @@ static void parse_options(char *options)static int pstore_show_options (struct seq_file *m,struct dentry *root) {if (kmsg_bytes !=CONFIG_PSTORE_DEFAULT_KMSG_BYTES ) -seq_printf (m,",kmsg_bytes=%lu" , kmsg_bytes); +seq_printf (m,",kmsg_bytes=%u" , kmsg_bytes);return 0 ; }
fs/pstore/internal.h +2 -2
@@ -6,7 +6,7 @@#include <linux/time.h> #include <linux/pstore.h> -extern unsigned long kmsg_bytes; +extern unsigned int kmsg_bytes;#ifdef CONFIG_PSTORE_FTRACE extern void pstore_register_ftrace (void );
@@ -35,7 +35,7 @@ static inline void pstore_unregister_pmsg(void) {}extern struct pstore_info *psinfo; -extern void pstore_set_kmsg_bytes (int ); +extern void pstore_set_kmsg_bytes (unsigned int bytes);extern void pstore_get_records (int );extern void pstore_get_backend_records (struct pstore_info *psi,struct dentry *root,int quiet);
fs/pstore/platform.c +6 -5
@@ -92,8 +92,8 @@ module_param(compress, charp, 0444);MODULE_PARM_DESC (compress,"compression to use" );/* How much of the kernel log to snapshot */ -unsigned long kmsg_bytes =CONFIG_PSTORE_DEFAULT_KMSG_BYTES ; -module_param (kmsg_bytes, ulong,0444 ); +unsigned int kmsg_bytes =CONFIG_PSTORE_DEFAULT_KMSG_BYTES ; +module_param (kmsg_bytes, uint,0444 );MODULE_PARM_DESC (kmsg_bytes,"amount of kernel log to snapshot (in bytes)" );static void *compress_workspace;
@@ -107,9 +107,9 @@ static void *compress_workspace;static char *big_oops_buf;static size_t max_compressed_size; -void pstore_set_kmsg_bytes (int bytes) +void pstore_set_kmsg_bytes (unsigned int bytes) { - kmsg_bytes = bytes; +WRITE_ONCE (kmsg_bytes, bytes); }/* Tag each group of saved records with a sequence number */
@@ -278,6 +278,7 @@ static void pstore_dump(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detail) {struct kmsg_dump_iter iter; +unsigned int remaining =READ_ONCE (kmsg_bytes);unsigned long total =0 ;const char *why;unsigned int part =1 ;
@@ -300,7 +301,7 @@ static void pstore_dump(struct kmsg_dumper *dumper,kmsg_dump_rewind (&iter); oopscount++; -while (total < kmsg_bytes) { +while (total < remaining) {char *dst;size_t dst_size;int header_size;
Signature · 1 line
2.34.1