Messages in this thread | | | From | Eiichi Tsukata <> | Subject | [PATCH 0/4] audit: refactor and fix for potential deadlock | Date | Mon, 8 May 2023 07:58:08 +0000 |
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Commit 7ffb8e317bae ("audit: we don't need to __set_current_state(TASK_RUNNING)") accidentally moved queue full check before add_wait_queue_exclusive() which introduced the following race:
CPU1 CPU2 ======== ======== (in audit_log_start()) (in kauditd_thread())
queue is full wake_up(&audit_backlog_wait) wait_event_freezable() add_wait_queue_exclusive() ... schedule_timeout()
Once this happens, both audit_log_start() and kauditd_thread() can cause deadlock for up to backlog_wait_time waiting for each other. To prevent the race, this patch adds queue full check after prepare_to_wait_exclusive().
This patchset consists of the following parts:
Patch 1-3: Refactorings and a small fix preferable for deadlock fix Patch 4: Actual deadlock fix
Eiichi Tsukata (4): audit: refactor queue full checks audit: account backlog waiting time in audit_receive() audit: convert DECLARE_WAITQUEUE to DEFINE_WAIT audit: check if queue is full after prepare_to_wait_exclusive()
kernel/audit.c | 71 ++++++++++++++++++++++++++++++-------------------- 1 file changed, 43 insertions(+), 28 deletions(-)
-- 2.40.0
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