Messages in this thread | | | Date | Fri, 20 Jun 2014 19:37:18 -0400 | From | Waiman Long <> | Subject | Re: [PATCH] selinux: no recursive read_lock of policy_rwlock in security_genfs_sid() |
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On 06/20/2014 01:49 PM, Stephen Smalley wrote: > On 06/20/2014 01:45 PM, Waiman Long wrote: >> With introduction of fair queued rwlock, recursive read_lock() may hang >> the offending process if there is a write_lock() somewhere in between. >> >> With recursive read_lock checking enabled, the following error was >> reported: >> >> ============================================= >> [ INFO: possible recursive locking detected ] >> 3.16.0-rc1 #2 Tainted: G E >> --------------------------------------------- >> load_policy/708 is trying to acquire lock: >> (policy_rwlock){.+.+..}, at: [<ffffffff8125b32a>] security_genfs_sid+0x3a/0x170 >> >> but task is already holding lock: >> (policy_rwlock){.+.+..}, at: [<ffffffff8125b48c>] security_fs_use+0x2c/0x110 >> >> other info that might help us debug this: >> Possible unsafe locking scenario: >> >> CPU0 >> ---- >> lock(policy_rwlock); >> lock(policy_rwlock); >> >> This patch fixes the occurrence of recursive read_lock() of >> policy_rwlock in security_genfs_sid() by adding a 5th argument to >> indicate if the rwlock has been taken. >> >> Signed-off-by: Waiman Long<Waiman.Long@hp.com> > Thanks, but I'd prefer to instead create a static helper function in > services.c that does not take the lock at all, use that function from > security_fs_use, and leave the extern function unmodified.
On second thought, this is exactly what I want to change the patch. I will send out a new one later today.
-Longman
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