Re: selftests: user_events: ftrace_test - RIP: 0010:tracing_update_buffers (kernel/trace/trace.c:6470)

Beau Belgrave
2023-10-30T16:50:14Z

On Mon, Oct 30, 2023 at 12:42:23PM -0400, Steven Rostedt wrote:
> On Mon, 30 Oct 2023 09:31:02 -0700
> Beau Belgrave <beaub@linux.microsoft.com> wrote:
>
> > I applied both [1][2] patches, and I no longer get any panics. However,
>
> Great! Can I add "Tested-by" from you on those patches?
>

Yep, please do.

> > I still get the splat about the trace_array_put when running
> > user_event's ftrace selftest:
> >
> > [ 26.665931] ------------[ cut here ]------------
> > [ 26.666663] WARNING: CPU: 12 PID: 291 at kernel/trace/trace.c:516 tracing_release_file_tr+0x46/0x50
> > [ 26.667470] Modules linked in:
> > [ 26.667808] CPU: 12 PID: 291 Comm: ftrace_test Not tainted 6.6.0-rc7-next-20231026 #3
> > [ 26.668665] RIP: 0010:tracing_release_file_tr+0x46/0x50
> > [ 26.669093] Code: d1 03 01 8b 83 c0 1e 00 00 85 c0 74 1d 83 e8 01 48 c7 c7 80 5b ef bc 89 83 c0 1e 00 00 e8 f2 b5 03 01 31 c0 5b e9 75 ee 27 01 <0f> 0b eb df 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90
> > [ 26.670580] RSP: 0018:ffffb6ef858ffee8 EFLAGS: 00010246
> > [ 26.671128] RAX: 0000000000000000 RBX: ffff9d7ae2364058 RCX: 0000000000000000
> > [ 26.671793] RDX: 0000000000000000 RSI: ffffffffbcb6b38b RDI: 00000000ffffffff
> > [ 26.672444] RBP: ffff9d7ac3e72200 R08: 0000000000000000 R09: 0000000000000000
> > [ 26.673072] R10: ffffb6ef858ffee8 R11: ffffffffbb28526f R12: 00000000000f801f
> > [ 26.673705] R13: ffff9d7b661a2020 R14: ffff9d7ac6057728 R15: 0000000000000000
> > [ 26.674339] FS: 00007fa852fa6740(0000) GS:ffff9d81a6300000(0000) knlGS:0000000000000000
> > [ 26.674978] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [ 26.675506] CR2: 00007fa852c2a250 CR3: 0000000105d92001 CR4: 0000000000370eb0
> > [ 26.676142] Call Trace:
> > [ 26.676357] <TASK>
> > [ 26.676572] ? __warn+0x7f/0x160
> > [ 26.677092] ? tracing_release_file_tr+0x46/0x50
> > [ 26.677540] ? report_bug+0x1c3/0x1d0
> > [ 26.677871] ? handle_bug+0x3c/0x70
> > [ 26.678196] ? exc_invalid_op+0x14/0x70
> > [ 26.678520] ? asm_exc_invalid_op+0x16/0x20
> > [ 26.678845] ? tracing_release_file_tr+0x1f/0x50
> > [ 26.679268] ? tracing_release_file_tr+0x46/0x50
> > [ 26.679691] ? tracing_release_file_tr+0x1f/0x50
> > [ 26.680105] __fput+0xab/0x300
> > [ 26.680437] __x64_sys_close+0x38/0x80
>
> Hmm, this doesn't tell me much. Let me go play with the user_event self
> tests.
>
> Thanks Beau!
>
> -- Steve

I get a 100% repro, so hopefully it's easy. Let me know if you can't or
if you need something tested.

Thanks,
-Beau

>
>
> > [ 26.680757] do_syscall_64+0x41/0xf0
> > [ 26.681329] entry_SYSCALL_64_after_hwframe+0x6c/0x74
> > [ 26.681784] RIP: 0033:0x7fa852d15157
> > [ 26.682126] Code: ff e8 0d 16 02 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 83 b8 f7 ff
> > [ 26.684255] RSP: 002b:00007ffd226914f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
> > [ 26.684939] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa852d15157
> > [ 26.685602] RDX: 0000000000000002 RSI: 0000560ad54567d4 RDI: 0000000000000005
> > [ 26.686257] RBP: 00007ffd22691520 R08: 0000000000000000 R09: 00007fa852fa6740
> > [ 26.686877] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd22691758
> > [ 26.687480] R13: 0000560ad5455ae7 R14: 0000560ad5458c38 R15: 00007fa8530d4040
> > [ 26.688107] </TASK>
> > [ 26.688315] irq event stamp: 1361
> > [ 26.688618] hardirqs last enabled at (1369): [<ffffffffbb1d7f49>] console_unlock+0x109/0x130
> > [ 26.689339] hardirqs last disabled at (1376): [<ffffffffbb1d7f2e>] console_unlock+0xee/0x130
> > [ 26.690062] softirqs last enabled at (1272): [<ffffffffbb14ba2a>] irq_exit_rcu+0x8a/0xe0
> > [ 26.690774] softirqs last disabled at (1267): [<ffffffffbb14ba2a>] irq_exit_rcu+0x8a/0xe0
> > [ 26.691620] ---[ end trace 0000000000000000 ]---
> >
> > Thanks,
> > -Beau
> >
> > 1. https://lore.kernel.org/linux-trace-kernel/20231030115018.25399dbd@gandalf.local.home/
> > 2. https://lore.kernel.org/linux-trace-kernel/20231028164650.4f5ea18a@rorschach.local.home/