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authorWanpeng Li <liwanp@linux.vnet.ibm.com>2013-09-11 14:23:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-11 15:58:12 -0700
commit3ba5eebc40a9839226e5f0d81a3e9f8fcfb8ebae (patch)
treedaf64f592a12315e48d91c783cb492eb8a8b80bc /mm
parent2d1e8b3f1acc36101dbe6c5fc14e88e3f6af0b1c (diff)
mm/memory-failure.c: fix bug triggered by unpoisoning empty zero page
Injecting memory failure for page 0x19d0 at 0xb77d2000 MCE 0x19d0: non LRU page recovery: Ignored MCE: Software-unpoisoned page 0x19d0 BUG: Bad page state in process bash pfn:019d0 page:f3461a00 count:0 mapcount:0 mapping: (null) index:0x0 page flags: 0x40000404(referenced|reserved) Modules linked in: nfsd auth_rpcgss i915 nfs_acl nfs lockd video drm_kms_helper drm bnep rfcomm sunrpc bluetooth psmouse parport_pc ppdev lp serio_raw fscache parport gpio_ich lpc_ich mac_hid i2c_algo_bit tpm_tis wmi usb_storage hid_generic usbhid hid e1000e firewire_ohci firewire_core ahci ptp libahci pps_core crc_itu_t CPU: 3 PID: 2123 Comm: bash Not tainted 3.11.0-rc6+ #12 Hardware name: LENOVO 7034DD7/ , BIOS 9HKT47AUS 01//2012 00000000 00000000 e9625ea0 c15ec49b f3461a00 e9625eb8 c15ea119 c17cbf18 ef084314 000019d0 f3461a00 e9625ed8 c110dc8a f3461a00 00000001 00000000 f3461a00 40000404 00000000 e9625ef8 c110dcc1 f3461a00 f3461a00 000019d0 Call Trace: dump_stack+0x41/0x52 bad_page+0xcf/0xeb free_pages_prepare+0x12a/0x140 free_hot_cold_page+0x21/0x110 __put_single_page+0x21/0x30 put_page+0x25/0x40 unpoison_memory+0x107/0x200 hwpoison_unpoison+0x20/0x30 simple_attr_write+0xb6/0xd0 vfs_write+0xa0/0x1b0 SyS_write+0x4f/0x90 sysenter_do_call+0x12/0x22 Disabling lock debugging due to kernel taint Testcase: #define _GNU_SOURCE #include <stdlib.h> #include <stdio.h> #include <sys/mman.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <errno.h> #define PAGES_TO_TEST 1 #define PAGE_SIZE 4096 int main(void) { char *mem; mem = mmap(NULL, PAGES_TO_TEST * PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); if (madvise(mem, PAGES_TO_TEST * PAGE_SIZE, MADV_HWPOISON) == -1) return -1; munmap(mem, PAGES_TO_TEST * PAGE_SIZE); return 0; } There is one page reference count for default empty zero page, madvise_hwpoison add another one by get_user_pages_fast. memory_hwpoison reduce one page reference count since it's a non LRU page. unpoison_memory release the last page reference count and free empty zero page to buddy system which is not correct since empty zero page has PG_reserved flag. This patch fix it by don't reduce the page reference count under 1 against empty zero page. Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memory-failure.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index d04f99004c9f..d472e14c6808 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1388,7 +1388,7 @@ int unpoison_memory(unsigned long pfn)
unlock_page(page);
put_page(page);
- if (freeit)
+ if (freeit && !(pfn == my_zero_pfn(0) && page_count(p) == 1))
put_page(page);
return 0;