New: memremap attempted on mixed range lockup.
Subsystems (4)
Andrew Morton
maintainer(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface).
Quoted 17 lines · On Fri, 08 Jun 2018 16:25:31 +0000 [email protected] wrote:
https://bugzilla.kernel.org/show_bug.cgi?id=199999
Bug ID: 199999 Summary: memremap attempted on mixed range lockup. Product: Memory Management Version: 2.5 Kernel Version: 4.14.48 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Other Assignee: [email protected] Reporter: [email protected] Regression: No
That WARN_ON in memremap() (soon perhaps devm_memremap_pages()) is triggering on /dev/mem.
Quoted 70 lines
hello. I was poking around and for no real reason, I did cat
/dev/memand strings/dev/mem.
Then I saw the following warning in dmesg. I saved it and rebooted immediately.Jun 08 19:07:25 hades kernel: memremap attempted on mixed range 0x000000000009c000 size: 0x1000 Jun 08 19:07:25 hades kernel: ------------[ cut here ]------------ Jun 08 19:07:25 hades kernel: WARNING: CPU: 0 PID: 11810 at kernel/memremap.c:98 memremap+0x104/0x170 Jun 08 19:07:25 hades kernel: Modules linked in: button isofs udf crc_itu_t loop nls_iso8859_1 nls_cp437 vfat fat uas usb_storage fuse bsd_comp ipt_MASQUERADE nf_nat_masquerade_ipv4 act_police sch_ingress cls_u32 sch_sfq iptable_nat nf_c> Jun 08 19:07:25 hades kernel: thermal snd_pcm snd_timer snd video soundcore shpchp mei_me mei fan i2c_i801 acpi_pad sch_fq_codel nvidia_uvm(PO) nvidia(PO) ipmi_devintf ipmi_msghandler nbd crypto_user ip_tables x_tables ext4 crc32c_gener> Jun 08 19:07:25 hades kernel: CPU: 0 PID: 11810 Comm: strings Tainted: P O 4.14.48-1-lts #1 Jun 08 19:07:25 hades kernel: Hardware name: LENOVO 90DA00D7AD/SKYBAY, BIOS FYKT58A 06/02/2016 Jun 08 19:07:25 hades kernel: task: ffff9393c0be3b00 task.stack: ffffb41287a3c000 Jun 08 19:07:25 hades kernel: RIP: 0010:memremap+0x104/0x170 Jun 08 19:07:25 hades kernel: RSP: 0018:ffffb41287a3fdc8 EFLAGS: 00010282 Jun 08 19:07:25 hades kernel: RAX: 0000000000000041 RBX: 0000000000000000 RCX: 0000000000000000 Jun 08 19:07:25 hades kernel: RDX: 0000000000000000 RSI: ffff9396bec165d8 RDI: ffff9396bec165d8 Jun 08 19:07:25 hades kernel: RBP: 0000000000000001 R08: 0000000000000412 R09: 0000000000000004 Jun 08 19:07:25 hades kernel: R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000001000 Jun 08 19:07:25 hades kernel: R13: 000055630d83b020 R14: ffff9396a5ec3000 R15: 0000000000000000 Jun 08 19:07:25 hades kernel: FS: 00007fa2611ddb80(0000) GS:ffff9396bec00000(0000) knlGS:0000000000000000 Jun 08 19:07:25 hades kernel: CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 Jun 08 19:07:25 hades kernel: CR2: 000055630d83c028 CR3: 00000001d5388006 CR4: 00000000003606f0 Jun 08 19:07:25 hades kernel: Call Trace: Jun 08 19:07:25 hades kernel: xlate_dev_mem_ptr+0x25/0x40 Jun 08 19:07:25 hades kernel: read_mem+0x89/0x1a0 Jun 08 19:07:25 hades kernel: __vfs_read+0x36/0x170 Jun 08 19:07:25 hades kernel: ? __fsnotify_parent+0x91/0x120 Jun 08 19:07:25 hades kernel: vfs_read+0x89/0x130 Jun 08 19:07:25 hades kernel: SyS_read+0x52/0xc0 Jun 08 19:07:25 hades kernel: do_syscall_64+0x67/0x120 Jun 08 19:07:25 hades kernel: entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Jun 08 19:07:25 hades kernel: RIP: 0033:0x7fa2609fd4a1 Jun 08 19:07:25 hades kernel: RSP: 002b:00007ffef180bb58 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 Jun 08 19:07:25 hades kernel: RAX: ffffffffffffffda RBX: 000055630d818470 RCX: 00007fa2609fd4a1 Jun 08 19:07:25 hades kernel: RDX: 0000000000001000 RSI: 000055630d83b020 RDI: 0000000000000003 Jun 08 19:07:25 hades kernel: RBP: 0000000000000d68 R08: 0000000000000000 R09: 0000000000000004 Jun 08 19:07:25 hades kernel: R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa260c94720 Jun 08 19:07:25 hades kernel: R13: 00007fa260c95260 R14: 00007ffef180bc14 R15: 00007ffef180bc08 Jun 08 19:07:25 hades kernel: Code: 48 83 c4 08 5b 5d 41 5c c3 80 3d 18 de f5 00 00 75 b7 4c 89 e2 48 89 e6 48 c7 c7 e8 db df 90 c6 05 02 de f5 00 01 e8 07 fa f4 ff <0f> 0b eb 9a 4c 89 e6 48 89 df e8 0d f8 ed ff 48 85 c0 74 99 48 Jun 08 19:07:25 hades kernel: ---[ end trace 5bdcf881c57b4daa ]---Signature · 2 lines
You are receiving this mail because: You are the assignee for the bug.
PATCH 1/1 mm: Fix devmem_is_allowed() for sub-page System RAM intersections
In reply to a message not in the archiveHussam reports:
I was poking around and for no real reason, I did cat /dev/mem and
strings /dev/mem. Then I saw the following warning in dmesg. I saved it
and rebooted immediately.
memremap attempted on mixed range 0x000000000009c000 size: 0x1000
------------[ cut here ]------------
WARNING: CPU: 0 PID: 11810 at kernel/memremap.c:98 memremap+0x104/0x170
[..]
Call Trace:
xlate_dev_mem_ptr+0x25/0x40
read_mem+0x89/0x1a0
__vfs_read+0x36/0x170The memremap() implementation checks for attempts to remap System RAM with MEMREMAP_WB and instead redirects those mapping attempts to the linear map. However, that only works if the physical address range being remapped is page aligned. In low memory we have situations like the following:
00000000-00000fff : Reserved
00001000-0009fbff : System RAM
0009fc00-0009ffff : Reserved...where System RAM intersects Reserved ranges on a sub-page page granularity.
Given that devmem_is_allowed() special cases any attempt to map System RAM in the first 1MB of memory, replace page_is_ram() with the more precise region_intersects() to trap attempts to map disallowed ranges.
Fixes 92281dee825f ("arch: introduce memremap()")
Cc <[email protected]>
Cc Christoph Hellwig <[email protected]>
Reported-by Hussam Al-Tayeb <[email protected]>
Signed-off-by Dan Williams <[email protected]>
--- arch/x86/mm/init.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
arch/x86/mm/init.c +3 -1
@@ -706,7 +706,9 @@ void __init init_mem_mapping(void)*/ int devmem_is_allowed (unsigned long pagenr) { -if (page_is_ram (pagenr)) { +if (region_intersects (PFN_PHYS (pagenr),PAGE_SIZE , +IORESOURCE_SYSTEM_RAM ,IORES_DESC_NONE ) + !=REGION_DISJOINT ) {/* * For disallowed memory regions in the low 1MB range, * request that the page be shown as all zeros.