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authoryangerkun <yangerkun@huawei.com>2021-06-16 03:23:32 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2021-06-16 18:24:42 +0200
commite8675d291ac007e1c636870db880f837a9ea112a (patch)
treeeaa74647e1e73ebafc7ee401cd19100fe97739b5 /mm
parentmm/hugetlb: expand restore_reserve_on_error functionality (diff)
downloadlinux-e8675d291ac007e1c636870db880f837a9ea112a.tar.xz
linux-e8675d291ac007e1c636870db880f837a9ea112a.zip
mm/memory-failure: make sure wait for page writeback in memory_failure
Our syzkaller trigger the "BUG_ON(!list_empty(&inode->i_wb_list))" in clear_inode: kernel BUG at fs/inode.c:519! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: Process syz-executor.0 (pid: 249, stack limit = 0x00000000a12409d7) CPU: 1 PID: 249 Comm: syz-executor.0 Not tainted 4.19.95 Hardware name: linux,dummy-virt (DT) pstate: 80000005 (Nzcv daif -PAN -UAO) pc : clear_inode+0x280/0x2a8 lr : clear_inode+0x280/0x2a8 Call trace: clear_inode+0x280/0x2a8 ext4_clear_inode+0x38/0xe8 ext4_free_inode+0x130/0xc68 ext4_evict_inode+0xb20/0xcb8 evict+0x1a8/0x3c0 iput+0x344/0x460 do_unlinkat+0x260/0x410 __arm64_sys_unlinkat+0x6c/0xc0 el0_svc_common+0xdc/0x3b0 el0_svc_handler+0xf8/0x160 el0_svc+0x10/0x218 Kernel panic - not syncing: Fatal exception A crash dump of this problem show that someone called __munlock_pagevec to clear page LRU without lock_page: do_mmap -> mmap_region -> do_munmap -> munlock_vma_pages_range -> __munlock_pagevec. As a result memory_failure will call identify_page_state without wait_on_page_writeback. And after truncate_error_page clear the mapping of this page. end_page_writeback won't call sb_clear_inode_writeback to clear inode->i_wb_list. That will trigger BUG_ON in clear_inode! Fix it by checking PageWriteback too to help determine should we skip wait_on_page_writeback. Link: https://lkml.kernel.org/r/20210604084705.3729204-1-yangerkun@huawei.com Fixes: 0bc1f8b0682c ("hwpoison: fix the handling path of the victimized page frame that belong to non-LRU") Signed-off-by: yangerkun <yangerkun@huawei.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Jan Kara <jack@suse.cz> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Oscar Salvador <osalvador@suse.de> Cc: Yu Kuai <yukuai3@huawei.com> 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.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 29ab7b70d326..0143d32bc666 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1552,7 +1552,12 @@ try_again:
return 0;
}
- if (!PageTransTail(p) && !PageLRU(p))
+ /*
+ * __munlock_pagevec may clear a writeback page's LRU flag without
+ * page_lock. We need wait writeback completion for this page or it
+ * may trigger vfs BUG while evict inode.
+ */
+ if (!PageTransTail(p) && !PageLRU(p) && !PageWriteback(p))
goto identify_page_state;
/*