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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-03 22:45:15 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-01-03 22:45:15 +0300 |
| commit | 360f0342b2e9374298e2222c846f3fe9d0295f0d (patch) | |
| tree | c485c0eaa39189891f6ff815a655262c9d7c4f5a | |
| parent | 981d04137a4b5ea95133572bdb3d888c9b515850 (diff) | |
| parent | fd56cd5f6d76e93356d9520cf9dabffe1e3d1aa0 (diff) | |
| download | linux-360f0342b2e9374298e2222c846f3fe9d0295f0d.tar.xz | |
Merge tag 'trace-v6.7-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix a NULL kernel dereference in set_gid() on tracefs mounting.
When tracefs is mounted with "gid=1000", it will update the existing
dentries to have the new gid. The tracefs_inode which is retrieved by
a container_of(dentry->d_inode) has flags to see if the inode belongs
to the eventfs system.
The issue that was fixed was if getdents() was called on tracefs that
was previously mounted, and was not closed. It will leave a "cursor
dentry" in the subdirs list of the current dentries that set_gid()
walks. On a remount of tracefs, the container_of(dentry->d_inode)
will dereference a NULL pointer and cause a crash when referenced.
Simply have a check for dentry->d_inode to see if it is NULL and if
so, skip that entry.
- Fix the bits of the eventfs_inode structure.
The "is_events" bit was taken from the nr_entries field, but the
nr_entries field wasn't updated to be 30 bits and was still 31.
Including the "is_freed" bit this would use 33 bits which would make
the structure use another integer for just one bit.
* tag 'trace-v6.7-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
eventfs: Fix bitwise fields for "is_events"
tracefs: Check for dentry->d_inode exists in set_gid()
| -rw-r--r-- | fs/tracefs/inode.c | 4 | ||||
| -rw-r--r-- | fs/tracefs/internal.h | 2 |
2 files changed, 5 insertions, 1 deletions
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 62524b20964e..bc86ffdb103b 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -215,6 +215,10 @@ resume: struct dentry *dentry = list_entry(tmp, struct dentry, d_child); next = tmp->next; + /* Note, getdents() can add a cursor dentry with no inode */ + if (!dentry->d_inode) + continue; + spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); change_gid(dentry, gid); diff --git a/fs/tracefs/internal.h b/fs/tracefs/internal.h index 899e447778ac..42bdeb471a07 100644 --- a/fs/tracefs/internal.h +++ b/fs/tracefs/internal.h @@ -63,7 +63,7 @@ struct eventfs_inode { }; unsigned int is_freed:1; unsigned int is_events:1; - unsigned int nr_entries:31; + unsigned int nr_entries:30; }; static inline struct tracefs_inode *get_tracefs(const struct inode *inode) |