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From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com,
	torvalds@linux-foundation.org, tglx@linutronix.de,
	mingo@kernel.org, namit@vmware.com, hpa@zytor.com,
	luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com
Subject: Re: [PATCH v3 5/6] x86/ftrace: Use text_poke()
Date: Wed, 9 Oct 2019 22:41:35 -0400	[thread overview]
Message-ID: <20191009224135.2dcf7767@oasis.local.home> (raw)
In-Reply-To: <20191008104335.6fcd78c9@gandalf.local.home>

On Tue, 8 Oct 2019 10:43:35 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:


> BTW, I'd really like to take this patch series through my tree. That
> way I can really hammer it, as well as I have code that will be built
> on top of it.

I did a bit of hammering and found two bugs. One I sent a patch to fix
(adding a module when tracing is enabled), but the other bug I
triggered, I'm too tired to debug right now. But figured I'd mention it
anyway.

If you add on the kernel command line:

 ftrace=function ftrace_filter=schedule

You will get this (note, I had KASAN enabled, so it showed more info):



[    1.274356] ftrace: allocating 34274 entries in 134 pages
[    1.320059] Starting tracer 'function'
[    1.323724] ==================================================================
[    1.330798] BUG: KASAN: null-ptr-deref in __get_locked_pte+0x21/0x210
[    1.337186] Read of size 8 at addr 0000000000000050 by task swapper/0
[    1.343579]
[    1.345049] CPU: 0 PID: 0 Comm: swapper Not tainted 5.4.0-rc2-test+ #50
[    1.351613] Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
[    1.360510] Call Trace:
[    1.362932]  dump_stack+0x7c/0xc0
[    1.366213]  ? __get_locked_pte+0x21/0x210
[    1.370272]  ? __get_locked_pte+0x21/0x210
[    1.374331]  __kasan_report.cold.10+0x5/0x3e
[    1.378566]  ? __get_locked_pte+0x21/0x210
[    1.382625]  kasan_report+0xe/0x20
[    1.385993]  __get_locked_pte+0x21/0x210
[    1.389880]  ? 0xffffffffa000005c
[    1.393162]  __text_poke+0x1ca/0x5b0
[    1.396705]  ? optimize_nops.isra.8+0xd0/0xd0
[    1.401023]  ? insn_get_length+0x4f/0x70
[    1.404910]  ? text_poke_loc_init+0x186/0x220
[    1.409229]  ? text_poke_kgdb+0x10/0x10
[    1.413031]  ? 0xffffffffa0000000
[    1.416312]  text_poke_bp_batch+0xb4/0x1e0
[    1.420372]  ? __text_poke+0x5b0/0x5b0
[    1.424088]  ? do_raw_spin_lock+0x113/0x1d0
[    1.428233]  ? 0xffffffffa000005c
[    1.431515]  ? 0xffffffffa0000000
[    1.434797]  text_poke_bp+0x7a/0xa0
[    1.438253]  ? text_poke_queue+0xb0/0xb0
[    1.442139]  ? 0xffffffffa0000000
[    1.445421]  ? 0xffffffffa000005c
[    1.448706]  ? find_vmap_area+0x56/0x80
[    1.452505]  arch_ftrace_update_trampoline+0x114/0x380
[    1.457603]  ? ftrace_caller+0x4e/0x4e
[    1.461316]  ? 0xffffffffa0000091
[    1.464599]  ? arch_ftrace_update_code+0x10/0x10
[    1.469179]  ? mutex_lock+0x86/0xd0
[    1.472634]  ? __mutex_lock_slowpath+0x10/0x10
[    1.477039]  ? mutex_unlock+0x1d/0x40
[    1.480668]  ? arch_jump_label_transform_queue+0x7a/0x90
[    1.485937]  ? __jump_label_update+0x91/0x140
[    1.490256]  ? mutex_unlock+0x1d/0x40
[    1.493885]  ? tracing_start_sched_switch.cold.0+0x60/0x60
[    1.499327]  __register_ftrace_function+0xaf/0xf0
[    1.503991]  ftrace_startup+0x24/0x130
[    1.507706]  register_ftrace_function+0x2d/0x80
[    1.512198]  function_trace_init+0xc1/0x100
[    1.516346]  tracing_set_tracer+0x1fb/0x3c0
[    1.520492]  ? free_snapshot+0x50/0x50
[    1.524205]  ? __kasan_kmalloc.constprop.6+0xc1/0xd0
[    1.529131]  ? __list_add_valid+0x29/0xa0
[    1.533106]  register_tracer+0x235/0x26c
[    1.536993]  early_trace_init+0x29b/0x3a0
[    1.540967]  start_kernel+0x2a3/0x5f7
[    1.544595]  ? mem_encrypt_init+0x6/0x6
[    1.548396]  ? load_ucode_intel_bsp+0x5e/0xa3
[    1.552715]  ? init_intel_microcode+0xc3/0xc3
[    1.557036]  ? load_ucode_bsp+0xcc/0x154
[    1.560923]  secondary_startup_64+0xa4/0xb0
[    1.565070] ==================================================================


-- Steve

  parent reply	other threads:[~2019-10-10  2:41 UTC|newest]

Thread overview: 128+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-07  9:02 [RESEND] everything text-poke: ftrace, modules, static_call and jump_label Peter Zijlstra
2019-10-07  8:17 ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Peter Zijlstra
2019-10-07  8:17   ` [PATCH v3 1/6] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-10-08 14:29     ` Borislav Petkov
2019-10-08 14:40       ` Steven Rostedt
2019-10-08 14:50         ` Borislav Petkov
2019-10-08 14:48       ` Peter Zijlstra
2019-10-08 14:54         ` Borislav Petkov
2019-10-08 15:04           ` Steven Rostedt
2019-10-08 15:24             ` Borislav Petkov
2019-10-09 12:03     ` Daniel Bristot de Oliveira
2019-10-07  8:17   ` [PATCH v3 2/6] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-10-07  8:17   ` [PATCH v3 3/6] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-10-09 12:04     ` Daniel Bristot de Oliveira
2019-10-07  8:17   ` [PATCH v3 4/6] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-10-08  6:23     ` Masami Hiramatsu
2019-10-08  8:15       ` Peter Zijlstra
2019-10-07  8:17   ` [PATCH v3 5/6] x86/ftrace: Use text_poke() Peter Zijlstra
2019-10-08 14:43     ` Steven Rostedt
2019-10-08 17:11       ` Peter Zijlstra
2019-10-08 17:27         ` Steven Rostedt
2019-10-10  2:41       ` Steven Rostedt [this message]
2019-10-10  9:20         ` Peter Zijlstra
2019-10-10 13:19           ` Steven Rostedt
2019-10-10 14:05             ` Peter Zijlstra
2019-10-10 15:54               ` Steven Rostedt
2019-10-10 17:28                 ` Peter Zijlstra
2019-10-10 17:48                   ` Steven Rostedt
2019-10-11 10:45                     ` Peter Zijlstra
2019-10-11 10:47                       ` Peter Zijlstra
2019-10-11 10:50                         ` Peter Zijlstra
2019-10-11 12:59                   ` Peter Zijlstra
2019-10-11 13:33                     ` Steven Rostedt
2019-10-11 13:45                       ` Peter Zijlstra
2019-10-15 13:07                     ` Jessica Yu
2019-10-15 13:56                       ` Peter Zijlstra
2019-10-15 14:11                         ` Peter Zijlstra
2019-10-15 14:13                         ` Miroslav Benes
2019-10-15 15:06                           ` Joe Lawrence
2019-10-15 15:31                             ` Jessica Yu
2019-10-15 22:17                               ` Joe Lawrence
2019-10-15 22:27                                 ` Steven Rostedt
2019-10-16  7:42                                   ` Peter Zijlstra
2019-10-16 10:15                                     ` Miroslav Benes
2019-10-21 15:05                                     ` Josh Poimboeuf
2020-01-20 16:50                                       ` Josh Poimboeuf
2020-01-21  8:35                                         ` Miroslav Benes
2020-01-21 16:10                                           ` Josh Poimboeuf
2020-01-22 10:09                                             ` Miroslav Benes
2020-01-22 21:42                                               ` Josh Poimboeuf
2020-01-28  9:28                                                 ` Miroslav Benes
2020-01-28 15:00                                                   ` Josh Poimboeuf
2020-01-28 15:40                                                     ` Petr Mladek
2020-01-28 17:02                                                       ` Josh Poimboeuf
2020-01-29  0:46                                                         ` Jiri Kosina
2020-01-29  2:17                                                           ` Josh Poimboeuf
2020-01-29  3:14                                                             ` Jiri Kosina
2020-01-29 12:28                                                         ` Miroslav Benes
2020-01-29 15:59                                                           ` Josh Poimboeuf
2020-01-30  9:53                                                             ` Petr Mladek
2020-01-30 14:17                                                               ` Josh Poimboeuf
2020-01-31  7:17                                                                 ` Petr Mladek
2020-01-22 12:15                                             ` Miroslav Benes
2020-01-22 15:05                                               ` Miroslav Benes
2020-01-22 22:03                                                 ` Josh Poimboeuf
2020-01-23 10:19                                                   ` Martin Jambor
2019-10-16  7:49                                   ` Peter Zijlstra
2019-10-16 10:20                                     ` Miroslav Benes
2019-10-16 13:29                                       ` Miroslav Benes
2019-10-18 13:03                                         ` Jessica Yu
2019-10-18 13:40                                           ` Petr Mladek
2019-10-21 14:14                                             ` Jessica Yu
2019-10-21 15:31                                             ` Josh Poimboeuf
2019-10-22  8:27                                           ` Miroslav Benes
2019-10-22 14:31                                             ` Josh Poimboeuf
2019-10-23  9:04                                               ` Miroslav Benes
2019-10-16  6:51                             ` Miroslav Benes
2019-10-16  9:23                               ` Peter Zijlstra
2019-10-16  9:36                                 ` Jessica Yu
2019-10-16  9:51                                   ` Peter Zijlstra
2019-10-16 12:39                               ` Peter Zijlstra
2019-10-22  8:45                                 ` Miroslav Benes
2019-10-15 14:42                         ` Peter Zijlstra
2019-10-15 18:31                           ` Peter Zijlstra
2019-10-15 15:51                         ` Jessica Yu
2019-10-15 13:28                     ` Steven Rostedt
2019-10-15 13:42                       ` Peter Zijlstra
2019-10-15 16:09                       ` Jessica Yu
2019-10-07  8:17   ` [PATCH v3 6/6] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-10-08 15:07   ` [PATCH v3 0/6] Rewrite x86/ftrace to use text_poke() Steven Rostedt
2019-10-07  8:25 ` [PATCH v2 0/4] Propagate module notifier errors Peter Zijlstra
2019-10-07  8:25   ` [PATCH v2 1/4] notifier: Fix broken error handling pattern Peter Zijlstra
2019-10-10 22:01     ` Rafael J. Wysocki
2019-10-07  8:25   ` [PATCH v2 2/4] module: Fix up module_notifier return values Peter Zijlstra
2019-10-23 19:25     ` Steven Rostedt
2019-10-07  8:25   ` [PATCH v2 3/4] module: Properly propagate MODULE_STATE_COMING failure Peter Zijlstra
2019-10-08 13:08     ` Miroslav Benes
2019-10-07  8:25   ` [PATCH v2 4/4] jump_label,module: Fix module lifetime for __jump_label_mod_text_reserved Peter Zijlstra
2019-10-23 19:29     ` Steven Rostedt
2019-10-07  8:27 ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 01/13] compiler.h: Make __ADDRESSABLE() symbol truly unique Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 02/13] static_call: Add basic static call infrastructure Peter Zijlstra
2019-10-07 11:33     ` Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 03/13] static_call: Add inline " Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 04/13] static_call: Avoid kprobes on inline static_call()s Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 05/13] x86/static_call: Add out-of-line static call implementation Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 06/13] x86/static_call: Add inline static call implementation for x86-64 Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 07/13] static_call: Simple self-test Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 08/13] tracepoints: Use static_call Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 09/13] x86/alternatives: Teach text_poke_bp() to emulate RET Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 10/13] static_call: Add static_cond_call() Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 11/13] static_call: Handle tail-calls Peter Zijlstra
2019-10-07  8:27   ` [PATCH v2 12/13] static_call: Allow early init Peter Zijlstra
2019-10-07  8:27   ` [RFC][PATCH v2 13/13] x86/perf, static_call: Optimize x86_pmu methods Peter Zijlstra
2019-10-07 11:33   ` [PATCH v2 00/13] Add static_call() Peter Zijlstra
2019-10-07  8:44 ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 1/9] jump_label, x86: Strip ASM " Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 2/9] jump_label, x86: Factor out the __jump_table generation Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 3/9] jump_label, x86: Remove init NOP optimization Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 4/9] jump_label, x86: Improve error when we fail expected text Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 5/9] jump_label, x86: Introduce jump_entry_size() Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 6/9] jump_label, x86: Add variable length patching support Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 7/9] jump_label,objtool: Validate variable size jump labels Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 8/9] jump_label,objtool: Generate possible statistics Peter Zijlstra
2019-10-07  8:44   ` [RFC][PATCH 9/9] jump_label, x86: Enable JMP8/NOP2 support Peter Zijlstra
2019-10-07 12:07   ` [RFC][PATCH 0/9] Variable size jump_label support Peter Zijlstra
2019-10-07 12:55     ` Ingo Molnar
2019-10-07 15:08       ` Steven Rostedt

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