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| author | Marc Dionne <marc.dionne@auristor.com> | 2019-08-22 15:28:43 +0300 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2019-08-22 15:33:26 +0300 |
| commit | c4c613ff08d92e72bf64a65ec35a2c3aa1cfcd06 (patch) | |
| tree | 2e5b2adfec2f534597e52aaa407802a438168ab8 | |
| parent | a5fb8e6c02d6a518fb2b1a2b8c2471fa77b69436 (diff) | |
| download | linux-c4c613ff08d92e72bf64a65ec35a2c3aa1cfcd06.tar.xz | |
afs: Fix possible oops in afs_lookup trace event
The afs_lookup trace event can cause the following:
[ 216.576777] BUG: kernel NULL pointer dereference, address: 000000000000023b
[ 216.576803] #PF: supervisor read access in kernel mode
[ 216.576813] #PF: error_code(0x0000) - not-present page
...
[ 216.576913] RIP: 0010:trace_event_raw_event_afs_lookup+0x9e/0x1c0 [kafs]
If the inode from afs_do_lookup() is an error other than ENOENT, or if it
is ENOENT and afs_try_auto_mntpt() returns an error, the trace event will
try to dereference the error pointer as a valid pointer.
Use IS_ERR_OR_NULL to only pass a valid pointer for the trace, or NULL.
Ideally the trace would include the error value, but for now just avoid
the oops.
Fixes: 80548b03991f ("afs: Add more tracepoints")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
| -rw-r--r-- | fs/afs/dir.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 81207dc3c997..139b4e3cc946 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -959,7 +959,8 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry, inode ? AFS_FS_I(inode) : NULL); } else { trace_afs_lookup(dvnode, &dentry->d_name, - inode ? AFS_FS_I(inode) : NULL); + IS_ERR_OR_NULL(inode) ? NULL + : AFS_FS_I(inode)); } return d; } |