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f2f26b4a84
Patch series "nilfs2: fix kernel bug at submit_bh_wbc()".
This resolves a kernel BUG reported by syzbot. Since there are two
flaws involved, I've made each one a separate patch.
The first patch alone resolves the syzbot-reported bug, but I think
both fixes should be sent to stable, so I've tagged them as such.
This patch (of 2):
Syzbot has reported a kernel bug in submit_bh_wbc() when writing file data
to a nilfs2 file system whose metadata is corrupted.
There are two flaws involved in this issue.
The first flaw is that when nilfs_get_block() locates a data block using
btree or direct mapping, if the disk address translation routine
nilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata
corruption, it can be passed back to nilfs_get_block(). This causes
nilfs_get_block() to misidentify an existing block as non-existent,
causing both data block lookup and insertion to fail inconsistently.
The second flaw is that nilfs_get_block() returns a successful status in
this inconsistent state. This causes the caller __block_write_begin_int()
or others to request a read even though the buffer is not mapped,
resulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc()
failing.
This fixes the first issue by changing the return value to code -EINVAL
when a conversion using DAT fails with code -ENOENT, avoiding the
conflicting condition that leads to the kernel bug described above. Here,
code -EINVAL indicates that metadata corruption was detected during the
block lookup, which will be properly handled as a file system error and
converted to -EIO when passing through the nilfs2 bmap layer.
Link: https://lkml.kernel.org/r/20240313105827.5296-1-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/20240313105827.5296-2-konishi.ryusuke@gmail.com
Fixes:
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.. | ||
alloc.c | ||
alloc.h | ||
bmap.c | ||
bmap.h | ||
btnode.c | ||
btnode.h | ||
btree.c | ||
btree.h | ||
cpfile.c | ||
cpfile.h | ||
dat.c | ||
dat.h | ||
dir.c | ||
direct.c | ||
direct.h | ||
export.h | ||
file.c | ||
gcinode.c | ||
ifile.c | ||
ifile.h | ||
inode.c | ||
ioctl.c | ||
Kconfig | ||
Makefile | ||
mdt.c | ||
mdt.h | ||
namei.c | ||
nilfs.h | ||
page.c | ||
page.h | ||
recovery.c | ||
segbuf.c | ||
segbuf.h | ||
segment.c | ||
segment.h | ||
sufile.c | ||
sufile.h | ||
super.c | ||
sysfs.c | ||
sysfs.h | ||
the_nilfs.c | ||
the_nilfs.h |