audit: drop BUG_ON() calls

PATCH Applied Ricardo Robaina 2 participants 7 messages Jul 28 Audit

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Ricardo Robaina

author

2026-07-28 14:14 UTC #0 lore raw

cover audit: drop BUG_ON() calls

This series drops two BUG_ON() calls from audit_add_to_parent() and audit_signal_info_syscall(), replacing them with alternatives that avoid panicking the kernel for conditions that are either debug-only assertions or defensive invariant checks.

Ricardo Robaina (2):
audit: drop BUG_ON() from audit_add_to_parent()
audit: drop BUG_ON() from audit_signal_info_syscall()

 kernel/audit_watch.c | 2 +-
 kernel/auditsc.c     | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

Signature · 1 line

2.53.0

Ricardo Robaina

author

2026-07-28 14:14 UTC #1 lore raw

PATCH 1/2 audit: drop BUG_ON() from audit_add_to_parent()

The BUG_ON(!mutex_is_locked(&audit_filter_mutex)) check in audit_add_to_parent() will panic the kernel if the mutex is not held, which is too severe for this situation.

Replace it with lockdep_assert_held(), instead.

Signed-off-by Ricardo Robaina <[email protected]>

---
 kernel/audit_watch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/audit_watch.c +1 -1

index 06dd0ebe73e2..4ac8a91e9ba8 100644
@@ -372,7 +372,7 @@ static void audit_add_to_parent(struct audit_krule *krule,
 	struct audit_watch *w, *watch = krule->watch;
 	int watch_found = 0;
 
-	BUG_ON(!mutex_is_locked(&audit_filter_mutex));
+	lockdep_assert_held(&audit_filter_mutex);
 
 	list_for_each_entry(w, &parent->watches, wlist) {
 		if (strcmp(watch->path, w->path))

Signature · 1 line

2.53.0

Paul Moore

maintainer Applied

2026-07-28 19:53 UTC #2 lore raw

Re: [PATCH 1/2] audit: drop BUG_ON() from audit_add_to_parent()

Quoted 11 lines · On Jul 28, 2026 Ricardo Robaina <[email protected]> wrote:

The BUG_ON(!mutex_is_locked(&audit_filter_mutex)) check in audit_add_to_parent() will panic the kernel if the mutex is not held, which is too severe for this situation.
Replace it with lockdep_assert_held(), instead.
Signed-off-by Ricardo Robaina <[email protected]>
---
 kernel/audit_watch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Merged into audit/dev, thanks.

--
paul-moore.com

Ricardo Robaina

author

2026-07-28 22:45 UTC #3 lore raw

Re: [PATCH 1/2] audit: drop BUG_ON() from audit_add_to_parent()

Quoted 14 lines · Paul Moore

Quoted 11 lines · On Jul 28, 2026 Ricardo Robaina <[email protected]> wrote:
The BUG_ON(!mutex_is_locked(&audit_filter_mutex)) check in audit_add_to_parent() will panic the kernel if the mutex is not held, which is too severe for this situation.
Replace it with lockdep_assert_held(), instead.
Signed-off-by Ricardo Robaina <[email protected]>
---
 kernel/audit_watch.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Quoted 5 lines

Merged into audit/dev, thanks.
--
paul-moore.com

Thanks, Paul!

Ricardo Robaina

author

2026-07-28 14:15 UTC #4 lore raw

PATCH 2/2 audit: drop BUG_ON() from audit_signal_info_syscall()

In reply to Ricardo Robaina

The BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS) check in audit_signal_info_syscall() will panic the kernel if the signal target pid array overflows, which is too severe for this situation.

Replace it with a WARN_ON_ONCE() and return of -EINVAL, instead.

Signed-off-by Ricardo Robaina <[email protected]>

---
 kernel/auditsc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

kernel/auditsc.c +2 -1

index 6610e667c728..2b9ce0b52511 100644
@@ -2712,7 +2712,8 @@ int audit_signal_info_syscall(struct task_struct *t)
 		axp->d.next = ctx->aux_pids;
 		ctx->aux_pids = (void *)axp;
 	}
-	BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS);
+	if (WARN_ON_ONCE(axp->pid_count >= AUDIT_AUX_PIDS))
+		return -EINVAL;
 
 	axp->target_pid[axp->pid_count] = task_tgid_nr(t);
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);

Signature · 1 line

2.53.0

Paul Moore

maintainer Applied

2026-07-28 19:53 UTC #5 lore raw

Re: [PATCH 2/2] audit: drop BUG_ON() from audit_signal_info_syscall()

Quoted 17 lines · On Jul 28, 2026 Ricardo Robaina <[email protected]> wrote:

The BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS) check in audit_signal_info_syscall() will panic the kernel if the signal target pid array overflows, which is too severe for this situation.
Replace it with a WARN_ON_ONCE() and return of -EINVAL, instead.
Signed-off-by Ricardo Robaina <[email protected]>
---
 kernel/auditsc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
kernel/auditsc.c +0 -0
index 6610e667c728..2b9ce0b52511 100644

kernel/auditsc.c int audit_signal_info_syscall(struct task_struct *t) · line 2716

Quoted 6 lines

kernel/auditsc.c +2 -1

@@ -2712,7 +2712,8 @@ int audit_signal_info_syscall(struct task_struct *t)
 		axp->d.next = ctx->aux_pids;
 		ctx->aux_pids = (void *)axp;
 	}
-	BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS);
+	if (WARN_ON_ONCE(axp->pid_count >= AUDIT_AUX_PIDS))
+		return -EINVAL;

Part of me wonders if the WARN_ON_ONCE() should be a pr_err(), possibly ratelimited, but given that I don't recall ever seeing this BUG_ON() trigger I think this is fine. We can always change the WARN_ON_ONCE() later if needed, getting rid of the BUG_ON() is the big win.

Merged into audit/dev, thanks.

Quoted 4 lines

kernel/auditsc.c +0 -0

 	axp->target_pid[axp->pid_count] = task_tgid_nr(t);
 	axp->target_auid[axp->pid_count] = audit_get_loginuid(t);

Signature · 1 line

2.53.0

--
paul-moore.com

Ricardo Robaina

author

2026-07-28 22:46 UTC #6 lore raw

Re: [PATCH 2/2] audit: drop BUG_ON() from audit_signal_info_syscall()

Quoted 31 lines · Paul Moore

Quoted 17 lines · On Jul 28, 2026 Ricardo Robaina <[email protected]> wrote:
The BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS) check in audit_signal_info_syscall() will panic the kernel if the signal target pid array overflows, which is too severe for this situation.
Replace it with a WARN_ON_ONCE() and return of -EINVAL, instead.
Signed-off-by Ricardo Robaina <[email protected]>
---
 kernel/auditsc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
kernel/auditsc.c +0 -0
index 6610e667c728..2b9ce0b52511 100644
kernel/auditsc.c int audit_signal_info_syscall(struct task_struct *t) · line 2716
Quoted 6 lines
kernel/auditsc.c +2 -1
@@ -2712,7 +2712,8 @@ int audit_signal_info_syscall(struct task_struct *t)
              axp->d.next = ctx->aux_pids;
              ctx->aux_pids = (void *)axp;
      }
-     BUG_ON(axp->pid_count >= AUDIT_AUX_PIDS);
+     if (WARN_ON_ONCE(axp->pid_count >= AUDIT_AUX_PIDS))
+             return -EINVAL;
Part of me wonders if the WARN_ON_ONCE() should be a pr_err(), possibly ratelimited, but given that I don't recall ever seeing this BUG_ON() trigger I think this is fine. We can always change the WARN_ON_ONCE() later if needed, getting rid of the BUG_ON() is the big win.

Quoted 1 line

Merged into audit/dev, thanks.

Makes sense. Thanks, Paul!

Quoted 9 lines

Quoted 5 lines

kernel/auditsc.c +0 -1

      axp->target_pid[axp->pid_count] = task_tgid_nr(t);
      axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
--

2.53.0

--
paul-moore.com