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author王贇 <yun.wang@linux.alibaba.com>2021-10-27 11:14:44 +0800
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2021-10-27 11:21:49 -0400
commitce5e48036c9e76a2a5bd4d9079eac273087a533a (patch)
tree5c85df7bf6acdfa7824314f02b07c3445dd7ef35 /include
parent2d2f6d4b8ce738ef43fc3436b43cecd2fea64152 (diff)
ftrace: disable preemption when recursion locked
As the documentation explained, ftrace_test_recursion_trylock() and ftrace_test_recursion_unlock() were supposed to disable and enable preemption properly, however currently this work is done outside of the function, which could be missing by mistake. And since the internal using of trace_test_and_set_recursion() and trace_clear_recursion() also require preemption disabled, we can just merge the logical. This patch will make sure the preemption has been disabled when trace_test_and_set_recursion() return bit >= 0, and trace_clear_recursion() will enable the preemption if previously enabled. Link: https://lkml.kernel.org/r/13bde807-779c-aa4c-0672-20515ae365ea@linux.alibaba.com CC: Petr Mladek <pmladek@suse.com> Cc: Guo Ren <guoren@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Helge Deller <deller@gmx.de> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: Joe Lawrence <joe.lawrence@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Jisheng Zhang <jszhang@kernel.org> CC: Steven Rostedt <rostedt@goodmis.org> CC: Miroslav Benes <mbenes@suse.cz> Reported-by: Abaci <abaci@linux.alibaba.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com> [ Removed extra line in comment - SDR ] Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/trace_recursion.h11
1 files changed, 10 insertions, 1 deletions
diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index 24f284eb55a7..a13f23b04d73 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -155,6 +155,9 @@ extern void ftrace_record_recursion(unsigned long ip, unsigned long parent_ip);
# define do_ftrace_record_recursion(ip, pip) do { } while (0)
#endif
+/*
+ * Preemption is promised to be disabled when return bit >= 0.
+ */
static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsigned long pip,
int start, int max)
{
@@ -189,14 +192,20 @@ static __always_inline int trace_test_and_set_recursion(unsigned long ip, unsign
current->trace_recursion = val;
barrier();
+ preempt_disable_notrace();
+
return bit + 1;
}
+/*
+ * Preemption will be enabled (if it was previously enabled).
+ */
static __always_inline void trace_clear_recursion(int bit)
{
if (!bit)
return;
+ preempt_enable_notrace();
barrier();
bit--;
trace_recursion_clear(bit);
@@ -209,7 +218,7 @@ static __always_inline void trace_clear_recursion(int bit)
* tracing recursed in the same context (normal vs interrupt),
*
* Returns: -1 if a recursion happened.
- * >= 0 if no recursion
+ * >= 0 if no recursion.
*/
static __always_inline int ftrace_test_recursion_trylock(unsigned long ip,
unsigned long parent_ip)