In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()
In the beginning of the loop, we try to obtain a locked delayed ref head,
if 'locked_ref' is currently NULL, by calling btrfs_select_ref_head(),
which can return an error pointer. If the error pointer is -EAGAIN we do
a continue and go back to the beginning of the loop, which will not try
again to call btrfs_select_ref_head() since 'locked_ref' is no longer
NULL but it's ERR_PTR(-EAGAIN), and then we do:
spin_lock(&locked_ref->lock);
against a ERR_PTR(-EAGAIN) value, generating an invalid pointer
dereference.
Fix this by ensuring that 'locked_ref' is set to NULL when
btrfs_select_ref_head() returns ERR_PTR(-EAGAIN) and incrementing 'count'
as well, to prevent infinite looping. We do this by doing a goto to the
bottom of the loop that already sets 'locked_ref' to NULL and does a
cond_resched(), with an increment to 'count' right before the goto.
These measures were in place before the refactoring in commit 0110a4c43451
("btrfs: refactor __btrfs_run_delayed_refs loop") but were unintentionally
lost afterwards.
References
Configurations
No configuration.
History
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Information
Published : 2026-08-15 06:22
Updated : 2026-08-17 06:19
NVD link : CVE-2026-74321
Mitre link : CVE-2026-74321
CVE.ORG link : CVE-2026-74321
JSON object : View
Products Affected
No product.
CWE
No CWE.