On 02/28/2013 11:27 AM, Greg Kroah-Hartman wrote: > On Thu, Feb 28, 2013 at 11:03:58AM -0500, Sasha Levin wrote: >> Hi Greg, >> >> While fuzzing with trinity inside a KVM tools guest, running latest -next kernel >> I got the following spew. >> >> The open() and release() callbacks in the traces below point to fs/sysfs/bin.c. > > Any hint as to which sysfs binary file you were accessing when this > happened? No, sorry - the trace only shows the allocation and freeing, I'm not sure which file it was. >> [ 719.288925] ============================================================================= >> [ 719.290663] BUG kmalloc-4096 (Tainted: G W ): Redzone overwritten >> [ 719.291764] ----------------------------------------------------------------------------- >> [ 719.291764] >> [ 719.294527] Disabling lock debugging due to kernel taint >> [ 719.294527] INFO: 0xffff88006d1a5520-0xffff88006d1a5520. First byte 0x0 instead of 0xcc >> [ 719.294527] INFO: Allocated in open+0xb8/0x190 age=18922 cpu=1 pid=7095 >> [ 719.294527] __slab_alloc+0x622/0x6d0 >> [ 719.294527] kmem_cache_alloc_trace+0x123/0x2c0 >> [ 719.294527] open+0xb8/0x190 >> [ 719.294527] do_dentry_open+0x229/0x330 >> [ 719.294527] finish_open+0x54/0x70 >> [ 719.294527] do_last+0x56c/0x790 >> [ 719.294527] path_openat+0xbe/0x490 >> [ 719.294527] do_filp_open+0x44/0xa0 >> [ 719.294527] do_sys_open+0x133/0x1d0 >> [ 719.294527] sys_open+0x1c/0x20 >> [ 719.294527] tracesys+0xdd/0xe2 >> [ 719.294527] INFO: Freed in seq_release+0x18/0x30 age=18947 cpu=0 pid=31203 >> [ 719.294527] __slab_free+0x3c/0x590 >> [ 719.294527] kfree+0x2cb/0x2e0 >> [ 719.294527] seq_release+0x18/0x30 >> [ 719.294527] single_release+0x24/0x40 >> [ 719.294527] proc_reg_release+0xed/0x110 >> [ 719.294527] __fput+0x122/0x2d0 >> [ 719.294527] ____fput+0x9/0x10 >> [ 719.294527] task_work_run+0xbe/0x100 >> [ 719.294527] do_notify_resume+0x7e/0xa0 >> [ 719.294527] int_signal+0x12/0x17 >> [ 719.294527] INFO: Slab 0xffffea0001b46800 objects=7 used=7 fp=0x (null) flags=0x1ffc0000004081 >> [ 719.294527] INFO: Object 0xffff88006d1a4520 @offset=17696 fp=0x (null) > > Hm, where is sysfs in this traceback? I don't see it mentioned anywhere > in this report, what am I missing? The call trace at the end of the spew: [ 719.294527] Call Trace: [ 719.294527] [<ffffffff81260202>] print_trailer+0x132/0x140 [ 719.294527] [<ffffffff81260641>] check_bytes_and_report+0xe1/0x130 [ 719.294527] [<ffffffff812626e2>] check_object+0x52/0x220 [ 719.294527] [<ffffffff81263a13>] free_debug_processing+0x173/0x300 [ 719.294527] [<ffffffff8130c9a2>] ? release+0x72/0x90 [ 719.294527] [<ffffffff8130c9a2>] ? release+0x72/0x90 [ 719.294527] [<ffffffff812674ec>] __slab_free+0x3c/0x590 [ 719.294527] [<ffffffff8118541d>] ? trace_hardirqs_on+0xd/0x10 [ 719.294527] [<ffffffff83d7a284>] ? _raw_spin_unlock_irqrestore+0x94/0xc0 [ 719.294527] [<ffffffff81a3898f>] ? __debug_check_no_obj_freed+0x15f/0x220 [ 719.294527] [<ffffffff83d75e89>] ? mutex_unlock+0x9/0x10 [ 719.294527] [<ffffffff8130c9a2>] ? release+0x72/0x90 [ 719.294527] [<ffffffff8130c9a2>] ? release+0x72/0x90 [ 719.294527] [<ffffffff81267d0b>] kfree+0x2cb/0x2e0 [ 719.294527] [<ffffffff8130c9a2>] release+0x72/0x90 [ 719.294527] [<ffffffff81289592>] __fput+0x122/0x2d0 [ 719.294527] [<ffffffff812897a9>] ____fput+0x9/0x10 [ 719.294527] [<ffffffff81135bbe>] task_work_run+0xbe/0x100 [ 719.294527] [<ffffffff81114781>] do_exit+0x311/0x510 [ 719.294527] [<ffffffff81114a21>] do_group_exit+0xa1/0xe0 [ 719.294527] [<ffffffff81114a72>] sys_exit_group+0x12/0x20 [ 719.294527] [<ffffffff83d833d0>] tracesys+0xdd/0xe2 Specifically, this: [ 719.294527] [<ffffffff8130c9a2>] release+0x72/0x90 Is the release() in fs/sysfs/bin.c I've confirmed it by also checking the sizes of the open() and release() sizes and actual code at those positions mentioned in the backtrace, and they match the backtrace. Thanks, Sasha -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>