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authorToshiyuki Okajima <toshi.okajima@jp.fujitsu.com>2013-12-05 16:15:23 +0900
committerEric Paris <eparis@redhat.com>2014-01-13 22:32:22 -0500
commit6dd80aba90639d1765396aa5e5f55e34dc3356e5 (patch)
tree5198fe1e1c3fe0bd4a1235414a93e108ce451c74 /kernel/audit.c
parent1b7b533f65db9b31f76972b2899ec7ec6433ae77 (diff)
downloadlinux-sh-6dd80aba90639d1765396aa5e5f55e34dc3356e5.tar.gz
audit: audit_log_start running on auditd should not stop
The backlog cannot be consumed when audit_log_start is running on auditd even if audit_log_start calls wait_for_auditd to consume it. The situation is the deadlock because only auditd can consume the backlog. If the other process needs to send the backlog, it can be also stopped by the deadlock. So, audit_log_start running on auditd should not stop. You can see the deadlock with the following reproducer: # auditctl -a exit,always -S all # reboot Signed-off-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com> Reviewed-by: gaofeng@cn.fujitsu.com Signed-off-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Eric Paris <eparis@redhat.com>
Diffstat (limited to 'kernel/audit.c')
-rw-r--r--kernel/audit.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/audit.c b/kernel/audit.c
index c05b6027e874..9c4ec29a707b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1319,7 +1319,8 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
struct audit_buffer *ab = NULL;
struct timespec t;
unsigned int uninitialized_var(serial);
- int reserve;
+ int reserve = 5; /* Allow atomic callers to go up to five
+ entries over the normal backlog limit */
unsigned long timeout_start = jiffies;
if (audit_initialized != AUDIT_INITIALIZED)
@@ -1328,11 +1329,12 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
if (unlikely(audit_filter_type(type)))
return NULL;
- if (gfp_mask & __GFP_WAIT)
- reserve = 0;
- else
- reserve = 5; /* Allow atomic callers to go up to five
- entries over the normal backlog limit */
+ if (gfp_mask & __GFP_WAIT) {
+ if (audit_pid && audit_pid == current->pid)
+ gfp_mask &= ~__GFP_WAIT;
+ else
+ reserve = 0;
+ }
while (audit_backlog_limit
&& skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {