From: Qian Cai <cai@lca.pw>
To: akpm@linux-foundation.org
Cc: ying.huang@intel.com, kirill.shutemov@linux.intel.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Qian Cai <cai@lca.pw>,
stable@vger.kernel.org
Subject: [PATCH] page-flags: fix a crash at SetPageError(THP_SWAP)
Date: Tue, 10 Mar 2020 19:58:46 -0400 [thread overview]
Message-ID: <20200310235846.1319-1-cai@lca.pw> (raw)
The commit bd4c82c22c36 ("mm, THP, swap: delay splitting THP after
swapped out") supported writing THP to a swap device but forgot to
upgrade an older commit df8c94d13c7e ("page-flags: define behavior of
FS/IO-related flags on compound pages") which could trigger a crash
during THP swapping out with DEBUG_VM_PGFLAGS=y,
kernel BUG at include/linux/page-flags.h:317!
page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page))
page:fffff3b2ec3a8000 refcount:512 mapcount:0 mapping:000000009eb0338c
index:0x7f6e58200 head:fffff3b2ec3a8000 order:9 compound_mapcount:0
compound_pincount:0
anon flags:
0x45fffe0000d8454(uptodate|lru|workingset|owner_priv_1|writeback|head|reclaim|swapbacked)
end_swap_bio_write()
SetPageError(page)
VM_BUG_ON_PAGE(1 && PageCompound(page))
<IRQ>
bio_endio+0x297/0x560
dec_pending+0x218/0x430 [dm_mod]
clone_endio+0xe4/0x2c0 [dm_mod]
bio_endio+0x297/0x560
blk_update_request+0x201/0x920
scsi_end_request+0x6b/0x4b0
scsi_io_completion+0x509/0x7e0
scsi_finish_command+0x1ed/0x2a0
scsi_softirq_done+0x1c9/0x1d0
__blk_mqnterrupt+0xf/0x20
</IRQ>
Fix by checking PF_NO_TAIL in those places instead.
Fixes: bd4c82c22c36 ("mm, THP, swap: delay splitting THP after swapped out")
Cc: <stable@vger.kernel.org>
Signed-off-by: Qian Cai <cai@lca.pw>
---
include/linux/page-flags.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 1bf83c8fcaa7..77de28bfefb0 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -311,7 +311,7 @@ static inline int TestClearPage##uname(struct page *page) { return 0; }
__PAGEFLAG(Locked, locked, PF_NO_TAIL)
PAGEFLAG(Waiters, waiters, PF_ONLY_HEAD) __CLEARPAGEFLAG(Waiters, waiters, PF_ONLY_HEAD)
-PAGEFLAG(Error, error, PF_NO_COMPOUND) TESTCLEARFLAG(Error, error, PF_NO_COMPOUND)
+PAGEFLAG(Error, error, PF_NO_TAIL) TESTCLEARFLAG(Error, error, PF_NO_TAIL)
PAGEFLAG(Referenced, referenced, PF_HEAD)
TESTCLEARFLAG(Referenced, referenced, PF_HEAD)
__SETPAGEFLAG(Referenced, referenced, PF_HEAD)
--
2.21.0 (Apple Git-122.2)
next reply other threads:[~2020-03-11 0:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-10 23:58 Qian Cai [this message]
2020-03-11 0:48 ` [PATCH] page-flags: fix a crash at SetPageError(THP_SWAP) Huang, Ying
2020-03-11 13:57 ` David Hildenbrand
2020-03-13 21:43 ` Rafael Aquini
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