2023-04-10 02:20:48

by Chao Yu

[permalink] [raw]
Subject: [PATCH] f2fs: fix to avoid use-after-free for cached IPU bio

xfstest generic/019 reports a bug:

kernel BUG at mm/filemap.c:1619!
RIP: 0010:folio_end_writeback+0x8a/0x90
Call Trace:
end_page_writeback+0x1c/0x60
f2fs_write_end_io+0x199/0x420
bio_endio+0x104/0x180
submit_bio_noacct+0xa5/0x510
submit_bio+0x48/0x80
f2fs_submit_write_bio+0x35/0x300
f2fs_submit_merged_ipu_write+0x2a0/0x2b0
f2fs_write_single_data_page+0x838/0x8b0
f2fs_write_cache_pages+0x379/0xa30
f2fs_write_data_pages+0x30c/0x340
do_writepages+0xd8/0x1b0
__writeback_single_inode+0x44/0x370
writeback_sb_inodes+0x233/0x4d0
__writeback_inodes_wb+0x56/0xf0
wb_writeback+0x1dd/0x2d0
wb_workfn+0x367/0x4a0
process_one_work+0x21d/0x430
worker_thread+0x4e/0x3c0
kthread+0x103/0x130
ret_from_fork+0x2c/0x50

The root cause is: after cp_error is set, f2fs_submit_merged_ipu_write()
in f2fs_write_single_data_page() tries to flush IPU bio in cache, however
f2fs_submit_merged_ipu_write() missed to check validity of @bio parameter,
result in submitting random cached bio which belong to other IO context,
then it will cause use-after-free issue, fix it by adding additional
validity check.

Fixes: 0b20fcec8651 ("f2fs: cache global IPU bio")
Signed-off-by: Chao Yu <[email protected]>
---
fs/f2fs/data.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 8064df5f829d..b59b5c7096f3 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -874,6 +874,8 @@ void f2fs_submit_merged_ipu_write(struct f2fs_sb_info *sbi,
bool found = false;
struct bio *target = bio ? *bio : NULL;

+ f2fs_bug_on(sbi, !target && !page);
+
for (temp = HOT; temp < NR_TEMP_TYPE && !found; temp++) {
struct f2fs_bio_info *io = sbi->write_io[DATA] + temp;
struct list_head *head = &io->bio_list;
@@ -2902,7 +2904,8 @@ int f2fs_write_single_data_page(struct page *page, int *submitted,

if (unlikely(f2fs_cp_error(sbi))) {
f2fs_submit_merged_write(sbi, DATA);
- f2fs_submit_merged_ipu_write(sbi, bio, NULL);
+ if (bio && *bio)
+ f2fs_submit_merged_ipu_write(sbi, bio, NULL);
submitted = NULL;
}

--
2.25.1


2023-04-11 17:01:57

by patchwork-bot+f2fs

[permalink] [raw]
Subject: Re: [f2fs-dev] [PATCH] f2fs: fix to avoid use-after-free for cached IPU bio

Hello:

This patch was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <[email protected]>:

On Mon, 10 Apr 2023 10:14:02 +0800 you wrote:
> xfstest generic/019 reports a bug:
>
> kernel BUG at mm/filemap.c:1619!
> RIP: 0010:folio_end_writeback+0x8a/0x90
> Call Trace:
> end_page_writeback+0x1c/0x60
> f2fs_write_end_io+0x199/0x420
> bio_endio+0x104/0x180
> submit_bio_noacct+0xa5/0x510
> submit_bio+0x48/0x80
> f2fs_submit_write_bio+0x35/0x300
> f2fs_submit_merged_ipu_write+0x2a0/0x2b0
> f2fs_write_single_data_page+0x838/0x8b0
> f2fs_write_cache_pages+0x379/0xa30
> f2fs_write_data_pages+0x30c/0x340
> do_writepages+0xd8/0x1b0
> __writeback_single_inode+0x44/0x370
> writeback_sb_inodes+0x233/0x4d0
> __writeback_inodes_wb+0x56/0xf0
> wb_writeback+0x1dd/0x2d0
> wb_workfn+0x367/0x4a0
> process_one_work+0x21d/0x430
> worker_thread+0x4e/0x3c0
> kthread+0x103/0x130
> ret_from_fork+0x2c/0x50
>
> [...]

Here is the summary with links:
- [f2fs-dev] f2fs: fix to avoid use-after-free for cached IPU bio
https://git.kernel.org/jaegeuk/f2fs/c/5cdb422c8391

You are awesome, thank you!
--
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