From: Masami Hiramatsu <mhiramat@kernel.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.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, jeyu@kernel.org,
alexei.starovoitov@gmail.com
Subject: Re: [PATCH -v5 00/17] Rewrite x86/ftrace to use text_poke (and more)
Date: Tue, 26 Nov 2019 18:58:09 +0900 [thread overview]
Message-ID: <20191126185809.91574fb8eb02f3b2dd3af863@kernel.org> (raw)
In-Reply-To: <20191126175812.c6e0cd1249422989007c91fe@kernel.org>
On Tue, 26 Nov 2019 17:58:12 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> Oops, I've tested a bit older kernel (with above change it seems to be fixed).
> I'll check the latest -tip.
Oops, it is reproduced.
+ wc -l
+ L=256
+ [ 256 -ne 256 ]
+ echo 1
[ 75.852865] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 75.855004] #PF: supervisor read access in kernel mode
[ 75.856579] #PF: error_code(0x0000) - not-present page
[ 75.858541] PGD 800000007bf60067 P4D 800000007bf60067 PUD 7bf5f067 PMD 0
[ 75.861420] Oops: 0000 [#1] PREEMPT SMP PTI
[ 75.863008] CPU: 6 PID: 0 Comm: swapper/6 Not tainted 5.4.0-rc8+ #23
[ 75.864881] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[ 75.870225] RIP: 0010:poke_int3_handler+0x39/0x100
[ 75.871672] Code: 5b 5d c3 f6 87 88 00 00 00 03 75 f2 48 8b 87 80 00 00 00 48 89 fb 48 8d 68 ff 48 8b 05 80 98 72 01 83 fa 01 0f 8f 93 00 00 00 <48> 63 10 48 81 c2 00 00 00 81 48 39 d5 75 c5 0f b6 50 08 8d 4a 34
[ 75.877927] RSP: 0018:ffffc900001a8eb8 EFLAGS: 00010046
[ 75.879794] RAX: 0000000000000000 RBX: ffffc900001a8ee8 RCX: ffffffff81a00b57
[ 75.881717] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffc900001a8ee8
[ 75.883632] RBP: ffffffff81027635 R08: 0000000000000000 R09: 0000000000000000
[ 75.885494] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 75.887360] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 75.889299] FS: 0000000000000000(0000) GS:ffff88807d980000(0000) knlGS:0000000000000000
[ 75.891668] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 75.893657] CR2: 0000000000000000 CR3: 000000007a970000 CR4: 00000000000006a0
[ 75.895307] Call Trace:
[ 75.896126] <IRQ>
[ 75.897191] do_int3+0xd/0xf0
[ 75.898710] int3+0x42/0x50
[ 75.900306] RIP: 0010:sched_clock+0x6/0x10
[ 75.901410] Code: d3 ea f6 c1 40 48 0f 45 c2 4c 01 c0 65 ff 0d 29 07 ff 7e 74 02 5d c3 e8 f0 a7 fd ff 5d c3 66 0f 1f 44 00 00 e8 ab f6 01 00 cc <90> c3 0f 1f 84 00 00 00 00 00 48 81 3d dd e5 21 01 c0 6f 02 81 0f
[ 75.905389] RSP: 0018:ffffc900001a8fc8 EFLAGS: 00000016
[ 75.906591] RAX: 00000011b208c72d RBX: 0000000000000000 RCX: 0000000000000000
[ 75.908690] RDX: 0000000000000004 RSI: 0000000000000004 RDI: ffffffff8275d180
[ 75.911009] RBP: 0000000000000000 R08: 0000002354a2e063 R09: 0000000000000001
[ 75.912981] R10: 0000000000000000 R11: ffff88807d1a9f18 R12: 0000000000000000
[ 75.914629] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 75.916351] ? sched_clock+0x6/0x10
[ 75.917475] ? sched_clock+0x5/0x10
[ 75.918742] sched_clock_cpu+0xe/0xd0
[ 75.920304] irq_exit+0xb3/0xc0
[ 75.921634] call_function_interrupt+0xf/0x20
[ 75.922918] </IRQ>
[ 75.923987] RIP: 0010:default_idle+0x23/0x180
[ 75.925386] Code: ff cc cc cc cc cc cc 41 55 41 54 55 53 e8 45 e8 c6 ff 0f 1f 44 00 00 e8 3b 25 95 ff e9 07 00 00 00 0f 00 2d 41 fd 5f 00 fb f4 <e8> 28 e8 c6 ff 89 c5 0f 1f 44 00 00 5b 5d 41 5c 41 5d c3 65 8b 05
[ 75.931117] RSP: 0018:ffffc9000008feb8 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff03
[ 75.933490] RAX: ffff88807d1a9680 RBX: 0000000000000006 RCX: 0000000000000000
[ 75.935047] RDX: 0000000000000046 RSI: 0000000000000006 RDI: ffff88807d1a9680
[ 75.936602] RBP: ffffffff8233dbc0 R08: 0000000000000001 R09: 0000000000000000
[ 75.938136] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 75.939726] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 75.941784] ? default_idle+0x15/0x180
[ 75.943147] default_idle_call+0x26/0x30
[ 75.944539] do_idle+0x1fe/0x220
[ 75.945618] ? trace_hardirqs_on+0x2c/0xf0
[ 75.946699] cpu_startup_entry+0x14/0x20
[ 75.948054] start_secondary+0x152/0x180
[ 75.949257] secondary_startup_64+0xb6/0xc0
[ 75.950287] Modules linked in: [last unloaded: trace_printk]
[ 75.951927] CR2: 0000000000000000
[ 75.953002] ---[ end trace f347ec44ad8fffbb ]---
[ 75.954322] RIP: 0010:poke_int3_handler+0x39/0x100
[ 75.956041] Code: 5b 5d c3 f6 87 88 00 00 00 03 75 f2 48 8b 87 80 00 00 00 48 89 fb 48 8d 68 ff 48 8b 05 80 98 72 01 83 fa 01 0f 8f 93 00 00 00 <48> 63 10 48 81 c2 00 00 00 81 48 39 d5 75 c5 0f b6 50 08 8d 4a 34
[ 75.960386] RSP: 0018:ffffc900001a8eb8 EFLAGS: 00010046
[ 75.961904] RAX: 0000000000000000 RBX: ffffc900001a8ee8 RCX: ffffffff81a00b57
[ 75.964994] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffffc900001a8ee8
[ 75.966836] RBP: ffffffff81027635 R08: 0000000000000000 R09: 0000000000000000
[ 75.968460] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[ 75.972194] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 75.973849] FS: 0000000000000000(0000) GS:ffff88807d980000(0000) knlGS:0000000000000000
[ 75.976592] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 75.978447] CR2: 0000000000000000 CR3: 000000007a970000 CR4: 00000000000006a0
[ 75.980548] Kernel panic - not syncing: Fatal exception
[ 75.982294] Kernel Offset: disabled
[ 75.983427] ---[ end Kernel panic - not syncing: Fatal exception ]---
QEMU: Terminated
mhiramat@devnote2:~/ksrc/mincs$ cd work/linux/build-x86_64/
mhiramat@devnote2:~/ksrc/mincs/work/linux/build-x86_64$ eu-addr2line -e ./vmlinux poke_int3_handler+0x39
/home/mhiramat/ksrc/mincs/work/linux/linux/arch/x86/kernel/alternative.c:958:20
static inline void *text_poke_addr(struct text_poke_loc *tp)
{
return _stext + tp->rel_addr; <------ Here is line #958
}
I applied following patch, but it seems not enough. While disabling 256 kprobes,
system was frozen (no BUG message).
Thank you,
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 4552795a8df4..9505096e2cd1 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -1134,8 +1134,14 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
* sync_core() implies an smp_mb() and orders this store against
* the writing of the new instruction.
*/
- bp_patching.vec = NULL;
bp_patching.nr_entries = 0;
+ /*
+ * This sync_core () ensures that all int3 handlers in progress
+ * have finished. This allows poke_int3_handler () after this to
+ * avoid touching bp_paching.vec by checking nr_entries == 0.
+ */
+ text_poke_sync();
+ bp_patching.vec = NULL;
}
void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2019-11-26 9:58 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-11 13:12 [PATCH -v5 00/17] Rewrite x86/ftrace to use text_poke (and more) Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 01/17] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 02/17] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 03/17] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] x86/alternatives, jump_label: " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 04/17] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-11-12 17:10 ` Steven Rostedt
2019-11-12 22:25 ` Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 05/17] x86/ftrace: Use text_poke() Peter Zijlstra
2019-11-12 18:25 ` Steven Rostedt
2019-11-12 22:24 ` Peter Zijlstra
2019-11-12 22:48 ` Steven Rostedt
2019-11-13 9:01 ` Peter Zijlstra
2019-11-13 14:27 ` Steven Rostedt
2019-11-14 13:18 ` Peter Zijlstra
2019-11-14 13:56 ` Steven Rostedt
2019-11-14 14:05 ` Peter Zijlstra
2019-11-13 8:53 ` Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-11-16 20:46 ` Borislav Petkov
2019-11-18 17:35 ` [PATCH] x86/ftrace: Mark ftrace_modify_code_direct() __ref Borislav Petkov
2019-11-18 17:52 ` Steven Rostedt
2019-11-19 9:55 ` [tip: core/kprobes] " tip-bot2 for Borislav Petkov
2019-12-04 8:33 ` tip-bot2 for Borislav Petkov
2019-12-04 8:33 ` [tip: core/kprobes] x86/ftrace: Use text_poke() tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 06/17] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 07/17] x86/alternative: Add text_opcode_size() Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 08/17] x86/ftrace: Use text_gen_insn() Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 09/17] x86/alternative: Remove text_poke_loc::len Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 10/17] x86/alternative: Shrink text_poke_loc Peter Zijlstra
2019-11-15 9:43 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 11/17] x86/kprobes: Convert to text-patching.h Peter Zijlstra
2019-11-19 16:56 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 12/17] x86/kprobes: Fix ordering Peter Zijlstra
2019-11-13 14:31 ` Paul E. McKenney
2019-11-13 15:42 ` Mathieu Desnoyers
2019-11-14 13:53 ` Peter Zijlstra
2019-11-14 15:06 ` Mathieu Desnoyers
2019-11-14 15:13 ` Paul E. McKenney
2019-11-14 15:22 ` Mathieu Desnoyers
2019-11-14 15:28 ` Peter Zijlstra
2019-11-14 15:30 ` Mathieu Desnoyers
2019-11-14 15:42 ` Peter Zijlstra
2019-11-14 15:58 ` Peter Zijlstra
2019-11-19 16:56 ` [tip: core/kprobes] x86/kprobes: Fix ordering while text-patching tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 13/17] arm/ftrace: Use __patch_text_real() Peter Zijlstra
2019-11-11 16:47 ` Will Deacon
2019-11-11 17:19 ` Peter Zijlstra
2019-11-11 17:25 ` Peter Zijlstra
2019-11-12 11:29 ` Will Deacon
2019-11-13 9:26 ` [PATCH -v5mkII 13/17] arm/ftrace: Use __patch_text() Peter Zijlstra
2019-11-19 16:56 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2020-01-22 21:26 ` Dmitry Osipenko
2020-02-07 10:17 ` Peter Zijlstra
2020-02-07 10:26 ` Peter Zijlstra
2020-02-07 11:27 ` Peter Zijlstra
2020-02-07 16:47 ` Dmitry Osipenko
2020-01-08 12:22 ` [PATCH -v5mkII 13/17] " Arnd Bergmann
2020-01-08 14:16 ` Steven Rostedt
2020-01-08 14:22 ` Arnd Bergmann
2019-11-11 13:13 ` [PATCH -v5 14/17] module: Remove set_all_modules_text_*() Peter Zijlstra
2019-11-19 16:56 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 15/17] ftrace: Rework event_create_dir() Peter Zijlstra
2019-11-14 14:07 ` Steven Rostedt
2019-11-19 16:56 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 16/17] x86/kprobe: Add comments to arch_{,un}optimize_kprobes() Peter Zijlstra
2019-11-19 16:56 ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 17/17] x86/alternative: Use INT3_INSN_SIZE Peter Zijlstra
2019-11-19 16:56 ` [tip: core/kprobes] x86/alternatives: " tip-bot2 for Peter Zijlstra
2019-12-04 8:33 ` tip-bot2 for Peter Zijlstra
2019-11-11 19:47 ` [PATCH -v5 00/17] Rewrite x86/ftrace to use text_poke (and more) Alexei Starovoitov
2019-11-11 20:39 ` Peter Zijlstra
2019-11-11 20:42 ` Peter Zijlstra
2019-11-11 20:56 ` Alexei Starovoitov
2019-11-12 18:26 ` Steven Rostedt
2019-11-25 3:55 ` Masami Hiramatsu
2019-11-25 6:47 ` Masami Hiramatsu
2019-11-25 17:32 ` Steven Rostedt
2019-11-26 0:11 ` Masami Hiramatsu
2019-11-26 8:58 ` Masami Hiramatsu
2019-11-26 9:58 ` Masami Hiramatsu [this message]
2019-11-26 23:48 ` Masami Hiramatsu
[not found] ` <CAADnVQK4twuXzFhD-qLHmCVK0n1h-GDENQLu+4PVV3Hp++R6kQ@mail.gmail.com>
2019-11-27 4:32 ` Alexei Starovoitov
2019-11-27 5:01 ` Alexei Starovoitov
2019-11-27 6:41 ` Masami Hiramatsu
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