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| author | David Howells <dhowells@redhat.com> | 2024-02-23 13:15:02 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-03-06 14:45:09 +0000 |
| commit | 058ed71e0f7aa3b6694ca357e23d084e5d3f2470 (patch) | |
| tree | aa0bf5e50bc9e0df57c245ca11109670de2c9ca3 | |
| parent | 2f91a96b892fab2f2543b4a55740c5bee36b1a6b (diff) | |
| download | linux-058ed71e0f7aa3b6694ca357e23d084e5d3f2470.tar.gz | |
afs: Fix endless loop in directory parsing
[ Upstream commit 5f7a07646655fb4108da527565dcdc80124b14c4 ]
If a directory has a block with only ".__afsXXXX" files in it (from
uncompleted silly-rename), these .__afsXXXX files are skipped but without
advancing the file position in the dir_context. This leads to
afs_dir_iterate() repeating the block again and again.
Fix this by making the code that skips the .__afsXXXX file also manually
advance the file position.
The symptoms are a soft lookup:
watchdog: BUG: soft lockup - CPU#3 stuck for 52s! [check:5737]
...
RIP: 0010:afs_dir_iterate_block+0x39/0x1fd
...
? watchdog_timer_fn+0x1a6/0x213
...
? asm_sysvec_apic_timer_interrupt+0x16/0x20
? afs_dir_iterate_block+0x39/0x1fd
afs_dir_iterate+0x10a/0x148
afs_readdir+0x30/0x4a
iterate_dir+0x93/0xd3
__do_sys_getdents64+0x6b/0xd4
This is almost certainly the actual fix for:
https://bugzilla.kernel.org/show_bug.cgi?id=218496
Fixes: 57e9d49c5452 ("afs: Hide silly-rename files from userspace")
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/786185.1708694102@warthog.procyon.org.uk
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Markus Suvanto <markus.suvanto@gmail.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/afs/dir.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c index cf811b77ee671f..6e2c967fae6fc2 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -478,8 +478,10 @@ static int afs_dir_iterate_block(struct afs_vnode *dvnode, dire->u.name[0] == '.' && ctx->actor != afs_lookup_filldir && ctx->actor != afs_lookup_one_filldir && - memcmp(dire->u.name, ".__afs", 6) == 0) + memcmp(dire->u.name, ".__afs", 6) == 0) { + ctx->pos = blkoff + next * sizeof(union afs_xdr_dirent); continue; + } /* found the next entry */ if (!dir_emit(ctx, dire->u.name, nlen, |