CVE-2026-46106
published 2026-05-28CVE-2026-46106: In the Linux kernel, the following vulnerability has been resolved: eventfs: Hold eventfs_mutex and SRCU when remount walks events Commit 340f0c7067a9…
medium5.5
In the Linux kernel, the following vulnerability has been resolved:
eventfs: Hold eventfs_mutex and SRCU when remount walks events
Commit 340f0c7067a9 ("eventfs: Update all the eventfs_inodes from the
events descriptor") had eventfs_set_attrs() recurse through ei->children
on remount. The walk only holds the rcu_read_lock() taken by
tracefs_apply_options() over tracefs_inodes, which is wrong:
- list_for_each_entry over ei->children races with the list_del_rcu()
in eventfs_remove_rec() -- LIST_POISON1 deref, same shape as
d2603279c7d6.
- eventfs_inodes are freed via call_srcu(&eventfs_srcu, ...).
rcu_read_lock() does not extend an SRCU grace period, so ti->private
can be reclaimed under the walk.
- The writes to ei->attr race with eventfs_set_attr(), which holds
eventfs_mutex.
Reproducer:
while :; do mount -o remount,uid=$((RANDOM%1000)) /sys/kernel/tracing; done &
while :; do
echo "p:kp submit_bio" > /sys/kernel/tracing/kprobe_events
echo > /sys/kernel/tracing/kprobe_events
done
Wrap the events portion of tracefs_apply_options() in
eventfs_remount_lock()/_unlock() that take eventfs_mutex and
srcu_read_lock(&eventfs_srcu). eventfs_set_attrs() doesn't sleep so the
nested rcu_read_lock() is fine; lockdep_assert_held() pins the contract.
Comment in tracefs_drop_inode() said "RCU cycle" -- it is SRCU.
Affected
10 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| linux | linux | — | — |
| linux | linux | — | — |
| linux | linux | >= 340f0c7067a95281ad13734f8225f49c6cf52067 < 44e64d8a432837308f4dda3ffe819f1ec092a0ba | 44e64d8a432837308f4dda3ffe819f1ec092a0ba |
| linux | linux | >= 340f0c7067a95281ad13734f8225f49c6cf52067 < 52b109f1b875b912d4ab2c5fdd8c322d47119d9b | 52b109f1b875b912d4ab2c5fdd8c322d47119d9b |
| linux | linux | >= 340f0c7067a95281ad13734f8225f49c6cf52067 < ed2ad73bcb0a7a6cc934097d4853b6d5124c317e | ed2ad73bcb0a7a6cc934097d4853b6d5124c317e |
| linux | linux | >= 340f0c7067a95281ad13734f8225f49c6cf52067 < 07004a8c4b572171934390148ee48c4175c77eed | 07004a8c4b572171934390148ee48c4175c77eed |
| linux | linux | >= 6.6.35 < 6.6.140 | 6.6.140 |
| linux | linux | >= 6.9.6 < 6.10 | 6.10 |
| linux | linux | >= 7ec535ed8724d18ae4e714d2277a5b89450659d2 < ae9cd0b46b1890040006a2fc5e905c5d6053fd02 | ae9cd0b46b1890040006a2fc5e905c5d6053fd02 |
| linux | linux_kernel | — | — |