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1f19093189
For the case of rtmutex torturing we will randomly call into the boost() handler, including upon module exiting when the tasks are deboosted before stopping. In such cases the task may or may not have already been boosted, and therefore the NULL being explicitly passed can occur anywhere. Currently we only assume that the task will is at a higher prio, and in consequence, dereference a NULL pointer. This patch fixes the case of a rmmod locktorture exploding while pounding on the rtmutex lock (partial trace): task: ffff88081026cf80 ti: ffff880816120000 task.ti: ffff880816120000 RSP: 0018:ffff880816123eb0 EFLAGS: 00010206 RAX: ffff88081026cf80 RBX: ffff880816bfa630 RCX: 0000000000160d1b RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000 RBP: ffff88081026cf80 R08: 000000000000001f R09: ffff88017c20ca80 R10: 0000000000000000 R11: 000000000048c316 R12: ffffffffa05d1840 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88203f880000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000001c0a000 CR4: 00000000000406e0 Stack: ffffffffa05d141d ffff880816bfa630 ffffffffa05d1922 ffff88081e70c2c0 ffff880816bfa630 ffffffff81095fed 0000000000000000 ffffffff8107bf60 ffff880816bfa630 ffffffff00000000 ffff880800000000 ffff880816123f08 Call Trace: [<ffffffff81095fed>] kthread+0xbd/0xe0 [<ffffffff815cf40f>] ret_from_fork+0x3f/0x70 This patch ensures that if the random state pointer is not NULL and current is not boosted, then do nothing. RIP: 0010:[<ffffffffa05c6185>] [<ffffffffa05c6185>] torture_random+0x5/0x60 [torture] [<ffffffffa05d141d>] torture_rtmutex_boost+0x1d/0x90 [locktorture] [<ffffffffa05d1922>] lock_torture_writer+0xe2/0x170 [locktorture] Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: bobby.prani@gmail.com Cc: dhowells@redhat.com Cc: dipankar@in.ibm.com Cc: dvhart@linux.intel.com Cc: edumazet@google.com Cc: fweisbec@gmail.com Cc: jiangshanlai@gmail.com Cc: josh@joshtriplett.org Cc: mathieu.desnoyers@efficios.com Cc: oleg@redhat.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/1460476038-27060-1-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| lglock.c | ||
| lockdep_internals.h | ||
| lockdep_proc.c | ||
| lockdep_states.h | ||
| lockdep.c | ||
| locktorture.c | ||
| Makefile | ||
| mcs_spinlock.h | ||
| mutex-debug.c | ||
| mutex-debug.h | ||
| mutex.c | ||
| mutex.h | ||
| osq_lock.c | ||
| percpu-rwsem.c | ||
| qrwlock.c | ||
| qspinlock_paravirt.h | ||
| qspinlock_stat.h | ||
| qspinlock.c | ||
| rtmutex_common.h | ||
| rtmutex-debug.c | ||
| rtmutex-debug.h | ||
| rtmutex.c | ||
| rtmutex.h | ||
| rwsem-spinlock.c | ||
| rwsem-xadd.c | ||
| rwsem.c | ||
| rwsem.h | ||
| semaphore.c | ||
| spinlock_debug.c | ||
| spinlock.c | ||