Date:   Tue, 18 Apr 2017 23:37:14 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: WARNING: kernel stack frame pointer has bad value

Josh,

I'm starting to get a bunch of these warnings, and I'm thinking they
are false positives. The stack frame error is recorded at a call from
entry_SYSCALL_64_fastpath, where I would expect the bp to not be valid.

To trigger this, I only need to go into /sys/kernel/debug/tracing and
echo function > current_tracer then cat trace. Maybe function tracer
stack frames is messing it up some how, but it always fails at the
entry call.

Here's the dump;

 WARNING: kernel stack frame pointer at ffff8800bda0ff30 in sshd:1090 has bad value 000055b32abf1fa8
 unwind stack type:0 next_sp:          (null) mask:6 graph_idx:0
 ffff8800bda0fd28: ffffffff81cf502a (entry_SYSCALL_64_fastpath+0x18/0xad)
 ffff8800bda0fd30: ffffffff810dc940 (sigprocmask+0x150/0x150)
 ffff8800bda0fd38: ffffffff81cf502a (entry_SYSCALL_64_fastpath+0x18/0xad)
 ffff8800bda0fd40: ffff8800c7e60040 (0xffff8800c7e60040)
 ffff8800bda0fd48: ffff8800bda0fe08 (0xffff8800bda0fe08)
 ffff8800bda0fd50: ffffffff825393c0 (ftrace_trace_arrays+0x40/0x40)
 ffff8800bda0fd58: ffff8800c7e60040 (0xffff8800c7e60040)
 ffff8800bda0fd60: 0000000000000008 (0x8)
 ffff8800bda0fd68: 00000000001a0800 (0x1a0800)
 ffff8800bda0fd70: 0000000000000000 ...
 ffff8800bda0fd78: fffffbfff04a727c (0xfffffbfff04a727c)
 ffff8800bda0fd80: ffffffff8122c8bb (trace_function+0x2b/0x120)
 ffff8800bda0fd88: dffffc0000000000 (0xdffffc0000000000)
 ffff8800bda0fd90: ffffffff810dc940 (sigprocmask+0x150/0x150)
 ffff8800bda0fd98: ffffffff825393e0 (global_trace+0x20/0x1680)
 ffff8800bda0fda0: ffffffffffffff7d (0xffffffffffffff7d)
 ffff8800bda0fda8: ffffffff8122c8bb (trace_function+0x2b/0x120)
 ffff8800bda0fdb0: 0000000000000010 (0x10)
 ffff8800bda0fdb8: 0000000000000246 (0x246)
 ffff8800bda0fdc0: ffff8800bda0fdd0 (0xffff8800bda0fdd0)
 ffff8800bda0fdc8: 0000000000000018 (0x18)
 ffff8800bda0fdd0: 00000000a02e0077 (0xa02e0077)
 ffff8800bda0fdd8: 0000000000000246 (0x246)
 ffff8800bda0fde0: ffff8800c7e60040 (0xffff8800c7e60040)
 ffff8800bda0fde8: ffff8800c7e60040 (0xffff8800c7e60040)
 ffff8800bda0fdf0: 0000000000000007 (0x7)
 ffff8800bda0fdf8: ffffffff810dc940 (sigprocmask+0x150/0x150)
 ffff8800bda0fe00: ffffffff81cf502a (entry_SYSCALL_64_fastpath+0x18/0xad)
 ffff8800bda0fe08: ffff8800bda0fe68 (0xffff8800bda0fe68)
 ffff8800bda0fe10: ffffffff81238168 (function_trace_call+0x208/0x260)
 ffff8800bda0fe18: 0000000000026f10 (0x26f10)
 ffff8800bda0fe20: ffff8800c7e621f0 (0xffff8800c7e621f0)
 ffff8800bda0fe28: 0000000000026f10 (0x26f10)
 ffff8800bda0fe30: ffff8800d3ea6f10 (0xffff8800d3ea6f10)
 ffff8800bda0fe38: 8000000000000010 (0x8000000000000010)
 ffff8800bda0fe40: 00007ffffd1f4e80 (0x7ffffd1f4e80)
 ffff8800bda0fe48: 00007ffffd1f4e00 (0x7ffffd1f4e00)
 ffff8800bda0fe50: 0000000000000000 ...
 ffff8800bda0fe58: 00007ffffd1f4f8f (0x7ffffd1f4f8f)
 ffff8800bda0fe60: 000055b32a9a2a51 (0x55b32a9a2a51)
 ffff8800bda0fe68: ffff8800bda0ff20 (0xffff8800bda0ff20)
 ffff8800bda0fe70: ffffffffa02e0077 (0xffffffffa02e0077)
 ffff8800bda0fe78: 000055b32bdc57c0 (0x55b32bdc57c0)
 ffff8800bda0fe80: 0000000041b58ab3 (0x41b58ab3)
 ffff8800bda0fe88: ffffffff8233e3f0 (ONEf+0x16e40/0x5840d)
 ffff8800bda0fe90: ffff8800bda0fed0 (0xffff8800bda0fed0)
 ffff8800bda0fe98: 000055b32abf1fa8 (0x55b32abf1fa8)
 ffff8800bda0fea0: ffff8800bda0fee0 (0xffff8800bda0fee0)
 ffff8800bda0fea8: ffff8800c7e60040 (0xffff8800c7e60040)
 ffff8800bda0feb0: ffffffff81cf5017 (entry_SYSCALL_64_fastpath+0x5/0xad)
 ffff8800bda0feb8: 00000000001a0800 (0x1a0800)
 ffff8800bda0fec0: 0000000000000000 ...
 ffff8800bda0fec8: 000000000000000e (0xe)
 ffff8800bda0fed0: 0000000000000008 (0x8)
 ffff8800bda0fed8: 00007ffffd1f4e00 (0x7ffffd1f4e00)
 ffff8800bda0fee0: 00007ffffd1f4e80 (0x7ffffd1f4e80)
 ffff8800bda0fee8: 0000000000000000 ...
 ffff8800bda0fef0: ffff8800bda0ff48 (0xffff8800bda0ff48)
 ffff8800bda0fef8: ffffffff810dc945 (SyS_rt_sigprocmask+0x5/0x1a0)
 ffff8800bda0ff00: ffff8800c7e60040 (0xffff8800c7e60040)
 ffff8800bda0ff08: 0000000000000008 (0x8)
 ffff8800bda0ff10: 00000000001a0800 (0x1a0800)
 ffff8800bda0ff18: 0000000000000000 ...
 ffff8800bda0ff20: ffff8800bda0ff30 (0xffff8800bda0ff30)
 ffff8800bda0ff28: ffffffff810dc945 (SyS_rt_sigprocmask+0x5/0x1a0)
 ffff8800bda0ff30: 000055b32abf1fa8 (0x55b32abf1fa8)
 ffff8800bda0ff38: ffffffff81cf502a (entry_SYSCALL_64_fastpath+0x18/0xad)
 ffff8800bda0ff40: 000055b32abf1fa8 (0x55b32abf1fa8)
 ffff8800bda0ff48: ffffffff810dc945 (SyS_rt_sigprocmask+0x5/0x1a0)
 ffff8800bda0ff50: ffffffff81cf502a (entry_SYSCALL_64_fastpath+0x18/0xad)
 ffff8800bda0ff58: 00000000258c9a9a (0x258c9a9a)
 ffff8800bda0ff60: 000000009a954c2d (0x9a954c2d)
 ffff8800bda0ff68: 00000000fc397de1 (0xfc397de1)
 ffff8800bda0ff70: 000000002badc874 (0x2badc874)
 ffff8800bda0ff78: ffff8800bda0ff98 (0xffff8800bda0ff98)
 ffff8800bda0ff80: ffffffff81149040 (trace_hardirqs_off_caller+0xc0/0x110)
 ffff8800bda0ff88: 0000000000000246 (0x246)
 ffff8800bda0ff90: 0000000000000008 (0x8)
 ffff8800bda0ff98: 00000000001a0800 (0x1a0800)
 ffff8800bda0ffa0: 0000000000000000 ...
 ffff8800bda0ffa8: ffffffffffffffda (0xffffffffffffffda)
 ffff8800bda0ffb0: 00007fb25d228c10 (0x7fb25d228c10)
 ffff8800bda0ffb8: 00007ffffd1f4e00 (0x7ffffd1f4e00)
 ffff8800bda0ffc0: 00007ffffd1f4e80 (0x7ffffd1f4e80)
 ffff8800bda0ffc8: 0000000000000000 ...
 ffff8800bda0ffd0: 000000000000000e (0xe)
 ffff8800bda0ffd8: 00007fb25d228c10 (0x7fb25d228c10)
 ffff8800bda0ffe0: 0000000000000033 (0x33)
 ffff8800bda0ffe8: 0000000000000246 (0x246)
 ffff8800bda0fff0: 00007ffffd1f4de8 (0x7ffffd1f4de8)
 ffff8800bda0fff8: 000000000000002b (0x2b)
 ------------[ cut here ]------------

I trigger this on 4.11-rc3 and I attached the config.

-- Steve

Download attachment "config.gz" of type "application/gzip" (27549 bytes)

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