diff options
| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-12-05 12:48:54 -0500 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2018-12-10 12:22:45 -0500 |
| commit | e4c07bf9867aeaec14bac042fbbd50d885f6ed3a (patch) | |
| tree | 65a13fd31c6dac570637999e7d0666401e43472d /arch/arm64/kernel/ftrace.c | |
| parent | a0572f687fb3c46e15554f4789797a077cc393b4 (diff) | |
arm64: ftrace: Set FTRACE_MAY_SLEEP before ftrace_modify_all_code()
It has been reported that ftrace_replace_code() which is called by
ftrace_modify_all_code() can cause a soft lockup warning for an
allmodconfig kernel. This is because all the debug options enabled
causes the loop in ftrace_replace_code() (which loops over all the
functions being enabled where there can be 10s of thousands), is too
slow, and never schedules out.
To solve this, setting FTRACE_MAY_SLEEP to the command passed into
ftrace_replace_code() will make it call cond_resched() in the loop,
which prevents the soft lockup warning from triggering.
Link: http://lkml.kernel.org/r/20181204192903.8193-1-anders.roxell@linaro.org
Link: http://lkml.kernel.org/r/20181205183304.000714627@goodmis.org
Acked-by: Will Deacon <will.deacon@arm.com>
Reported-by: Anders Roxell <anders.roxell@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'arch/arm64/kernel/ftrace.c')
| -rw-r--r-- | arch/arm64/kernel/ftrace.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 57e962290df3..57d4e936a176 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -193,6 +193,7 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, void arch_ftrace_update_code(int command) { + command |= FTRACE_MAY_SLEEP; ftrace_modify_all_code(command); } |