[PATCH v5 0/2] fix & prevent the missing preemption disabling
flat view
From: 王贇 <hidden>
Date: 2021-10-26 03:14:15
Also in:
linux-riscv, live-patching, lkml
Subsystem:
c-sky architecture, function hooks (ftrace), linux for powerpc (32-bit and 64-bit), live patching, parisc architecture, risc-v architecture, the rest, tracing, x86 architecture (32-bit and 64-bit) · Maintainers:
Guo Ren, Steven Rostedt, Masami Hiramatsu, Madhavan Srinivasan, Josh Poimboeuf, Miroslav Benes, Petr Mladek, Joe Lawrence, Song Liu, "James E.J. Bottomley", Helge Deller, Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Status: Superseded by v7 (posted 2021-10-27). [go to v7]
Revision v5 (6 revisions archived).
Revisions (6)
The testing show that perf_ftrace_function_call() are using smp_processor_id() with preemption enabled, all the checking on CPU could be wrong after preemption. As Peter point out, the section between ftrace_test_recursion_trylock/unlock() pair require the preemption to be disabled as 'Documentation/trace/ftrace-uses.rst' explained, but currently the work is done outside of the helpers. And since the internal using of trace_test_and_set_recursion() and trace_clear_recursion() also require preemption to be disabled, we can just merge the logical together. Patch 1/2 will make sure preemption disabled when recursion lock succeed, patch 2/2 will do smp_processor_id() checking after trylock() to address the issue. v1: https://lore.kernel.org/all/8c7de46d-9869-aa5e-2bb9-5dbc2eda395e@linux.alibaba.com/ (local) v2: https://lore.kernel.org/all/b1d7fe43-ce84-0ed7-32f7-ea1d12d0b716@linux.alibaba.com/ (local) v3: https://lore.kernel.org/all/609b565a-ed6e-a1da-f025-166691b5d994@linux.alibaba.com/ (local) V4: https://lore.kernel.org/all/32a36348-69ee-6464-390c-3a8d6e9d2b53@linux.alibaba.com/ (local) Michael Wang (2): ftrace: disable preemption when recursion locked ftrace: do CPU checking after preemption disabled arch/csky/kernel/probes/ftrace.c | 2 -- arch/parisc/kernel/ftrace.c | 2 -- arch/powerpc/kernel/kprobes-ftrace.c | 2 -- arch/riscv/kernel/probes/ftrace.c | 2 -- arch/x86/kernel/kprobes/ftrace.c | 2 -- include/linux/trace_recursion.h | 11 ++++++++++- kernel/livepatch/patch.c | 13 +++++++------ kernel/trace/ftrace.c | 15 +++++---------- kernel/trace/trace_event_perf.c | 6 +++--- kernel/trace/trace_functions.c | 5 ----- 10 files changed, 25 insertions(+), 35 deletions(-) -- 1.8.3.1