On Wed, Jun 13, 2018 at 06:47:02AM -0700, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: 73fcb1a370c7 Merge branch 'akpm' (patches from Andrew) > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=16d70827800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f3b4e30da84ec1ed > dashboard link: https://syzkaller.appspot.com/bug?extid=e5579222b6a3edd96522 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=176daf97800000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15e7bd57800000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+e5579222b6a3edd96522@xxxxxxxxxxxxxxxxxxxxxxxxx > > > ===================================== > WARNING: bad unlock balance detected! > 4.17.0-rc5+ #58 Not tainted > kworker/u4:0/6 is trying to release lock (&file->mut) at: > [<ffffffff8593ecc0>] ucma_event_handler+0x780/0xff0 > drivers/infiniband/core/ucma.c:390 > but there are no more locks to release! > > other info that might help us debug this: > 4 locks held by kworker/u4:0/6: > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: > __write_once_size include/linux/compiler.h:215 [inline] > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: > arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: atomic64_set > include/asm-generic/atomic-instrumented.h:40 [inline] > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: atomic_long_set > include/asm-generic/atomic-long.h:57 [inline] > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: set_work_data > kernel/workqueue.c:617 [inline] > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: > set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] > #0: (ptrval) ((wq_completion)"ib_addr"){+.+.}, at: > process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 > #1: (ptrval) ((work_completion)(&(&req->work)->work)){+.+.}, at: > process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 > #2: (ptrval) (&id_priv->handler_mutex){+.+.}, at: > addr_handler+0xa6/0x3d0 drivers/infiniband/core/cma.c:2796 > #3: (ptrval) (&file->mut){+.+.}, at: ucma_event_handler+0x10e/0xff0 > drivers/infiniband/core/ucma.c:350 I think this is probably a use-after-free race, eg when we do ctx->file->mut we have raced with ucma_free_ctx() .. Which probably means something along the way to free_ctx() did not call rdma_addr_cancel? Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
