perf/ftrace: fuzzer triggers another warning with PERF_EVENT_IOC_SET_FILTER

[Vince Weaver]

The fuzzer triggered another warning in the PERF_EVENT_IOC_SET_FILTER 
code.  This is with the previous filter patch applied.

>From what I can tell the filter was:
nfs4:nfs4_fsinfo 
(((fhandle~601)&&valid&809)&&common_type>=860) 

The warning in question:
	WARN_ON_ONCE(cnt < 0);
in check_preds().

[65903.660154] WARNING: CPU: 1 PID: 731 at kernel/trace/trace_events_filter.c:1388 replace_preds+0x2e4/0xa50()
[65903.748080] CPU: 1 PID: 731 Comm: perf_fuzzer Tainted: G        W       4.1.0-rc8+ #157
[65903.757203] Hardware name: LENOVO 10AM000AUS/SHARKBAY, BIOS FBKT72AUS 01/26/2014
[65903.765711]  ffffffff81a1ac00 ffff880117117cb8 ffffffff816d7419 0000000000000000
[65903.774323]  0000000000000000 ffff880117117cf8 ffffffff81072eba 0000000000000005
[65903.782924]  0000000000000003 ffff8800366bd018 ffff8800366bd000 ffff8800cf3e9220
[65903.791516] Call Trace:
[65903.794688]  [<ffffffff816d7419>] dump_stack+0x45/0x57
[65903.800732]  [<ffffffff81072eba>] warn_slowpath_common+0x8a/0xc0
[65903.807712]  [<ffffffff81072faa>] warn_slowpath_null+0x1a/0x20
[65903.814477]  [<ffffffff8114b1c4>] replace_preds+0x2e4/0xa50
[65903.820974]  [<ffffffff8114c2c3>] ? ftrace_profile_set_filter+0x23/0x100
[65903.828640]  [<ffffffff8114b9b2>] create_filter+0x82/0xb0
[65903.834917]  [<ffffffff8114c2f4>] ftrace_profile_set_filter+0x54/0x100
[65903.842436]  [<ffffffff811909eb>] ? strndup_user+0x4b/0xc0
[65903.848794]  [<ffffffff81166290>] perf_ioctl+0x170/0x4d0
[65903.854959]  [<ffffffff812023d0>] do_vfs_ioctl+0x2e0/0x4e0
[65903.861286]  [<ffffffff816dcdfe>] ? mutex_unlock+0xe/0x10
[65903.867492]  [<ffffffff81164756>] ? perf_event_task_enable+0xb6/0xd0
[65903.874754]  [<ffffffff81202651>] SyS_ioctl+0x81/0xa0
[65903.880655]  [<ffffffff816df372>] system_call_fastpath+0x16/0x7a
[65903.887534] ---[ end trace 48137d0593a025d9 ]---
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/