From: Masami Hiramatsu <mhiramat@kernel.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>, Ingo Molnar <mingo@kernel.org>
Cc: X86 ML <x86@kernel.org>, Masami Hiramatsu <mhiramat@kernel.org>,
Daniel Xu <dxu@dxuuu.xyz>,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
kuba@kernel.org, mingo@redhat.com, ast@kernel.org,
tglx@linutronix.de, kernel-team@fb.com, yhs@fb.com,
Steven Rostedt <rostedt@goodmis.org>
Subject: [RFC PATCH -tip 0/3] x86/kprobes,orc: Fix ORC unwinder to unwind stack with optimized probe
Date: Wed, 31 Mar 2021 14:44:24 +0900 [thread overview]
Message-ID: <161716946413.721514.4057380464113663840.stgit@devnote2> (raw)
Hello,
These patches fixes the ORC unwinder to unwind optprobe trampoline
code on the stack correctly.
This patchset is based on the kretporbe and stacktrace fix series v5
which I sent last week.
https://lore.kernel.org/bpf/161676170650.330141.6214727134265514123.stgit@devnote2/
Note that I just confirmed the it fixes the case where the
stacktrace called from the optprobe handler. So this should be
carefully reviewed.
Here is the test code;
cd /sys/kernel/debug/tracing
echo > trace
echo p full_proxy_read+5 >> kprobe_events
echo 1 > events/kprobes/enable
sleep 1 # wait for optimization
echo stacktrace:1 > events/kprobes/p_full_proxy_read_5/trigger
echo 1 > options/sym-offset
cat /sys/kernel/debug/kprobes/list
Without this,
cat-138 [001] ...1 6.567662: p_full_proxy_read_5: (full_proxy_read+0x5/0x80)
cat-138 [001] ...1 6.567711: <stack trace>
=> kprobe_trace_func+0x1d0/0x2c0
=> kprobe_dispatcher+0x39/0x60
=> opt_pre_handler+0x4f/0x80
=> optimized_callback+0xc3/0xf0
=> 0xffffffffa0006032
=> 0
=> 0
With this patch,
cat-137 [007] ...1 17.542848: p_full_proxy_read_5: (full_proxy_read+0x5/0x80)
cat-137 [007] ...1 17.542963: <stack trace>
=> kprobe_trace_func+0x1d0/0x2c0
=> kprobe_dispatcher+0x39/0x60
=> opt_pre_handler+0x4f/0x80
=> optimized_callback+0xc3/0xf0
=> full_proxy_read+0x5/0x80
=> vfs_read+0xab/0x1a0
=> ksys_read+0x5f/0xe0
=> do_syscall_64+0x33/0x40
=> entry_SYSCALL_64_after_hwframe+0x44/0xae
=> 0
=> 0
Thank you,
---
Masami Hiramatsu (3):
x86/kprobes: Add ORC information to optprobe template
kprobes: Add functions to find instruction buffer entry address
x86/kprobes,orc: Unwind optprobe trampoline correctly
arch/x86/include/asm/kprobes.h | 6 +++
arch/x86/kernel/kprobes/opt.c | 72 +++++++++++++++++++++++++++++++++++++---
arch/x86/kernel/unwind_orc.c | 15 +++++++-
include/linux/kprobes.h | 8 ++++
kernel/kprobes.c | 25 ++++++++++----
5 files changed, 111 insertions(+), 15 deletions(-)
--
Masami Hiramatsu (Linaro) <mhiramat@kernel.org>
next reply other threads:[~2021-03-31 5:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-31 5:44 Masami Hiramatsu [this message]
2021-03-31 5:44 ` [RFC PATCH -tip 1/3] x86/kprobes: Add ORC information to optprobe template Masami Hiramatsu
2021-03-31 5:44 ` [RFC PATCH -tip 2/3] kprobes: Add functions to find instruction buffer entry address Masami Hiramatsu
2021-03-31 5:44 ` [RFC PATCH -tip 3/3] x86/kprobes,orc: Unwind optprobe trampoline correctly Masami Hiramatsu
2021-03-31 15:57 ` Josh Poimboeuf
2021-04-01 1:44 ` Masami Hiramatsu
2021-04-01 2:19 ` Masami Hiramatsu
2021-04-01 1:54 ` Masami Hiramatsu
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