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| author | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-05 21:32:39 -0500 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-11-06 08:33:23 -0500 |
| commit | 6cdf941871ec9cb1cf03227038a45a73afd8dc9a (patch) | |
| tree | db2e7e2c3b1088b873fb25076d55331ec3564401 /fs/pstore | |
| parent | da5afbeb1724609996ca7bb4fbce2cd104c95914 (diff) | |
| download | lwn-6cdf941871ec9cb1cf03227038a45a73afd8dc9a.tar.gz lwn-6cdf941871ec9cb1cf03227038a45a73afd8dc9a.zip | |
pstore/ftrace: Add recursion protection to the ftrace callback
If a ftrace callback does not supply its own recursion protection and
does not set the RECURSION_SAFE flag in its ftrace_ops, then ftrace will
make a helper trampoline to do so before calling the callback instead of
just calling the callback directly.
The default for ftrace_ops is going to change. It will expect that handlers
provide their own recursion protection, unless its ftrace_ops states
otherwise.
Link: https://lkml.kernel.org/r/20201028115612.990886844@goodmis.org
Link: https://lkml.kernel.org/r/20201106023546.720372267@goodmis.org
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Meyer <thomas@m3y3r.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'fs/pstore')
| -rw-r--r-- | fs/pstore/ftrace.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c index 5c0450701293..816210fc5d3a 100644 --- a/fs/pstore/ftrace.c +++ b/fs/pstore/ftrace.c @@ -28,6 +28,7 @@ static void notrace pstore_ftrace_call(unsigned long ip, struct ftrace_ops *op, struct pt_regs *regs) { + int bit; unsigned long flags; struct pstore_ftrace_record rec = {}; struct pstore_record record = { @@ -40,6 +41,10 @@ static void notrace pstore_ftrace_call(unsigned long ip, if (unlikely(oops_in_progress)) return; + bit = ftrace_test_recursion_trylock(); + if (bit < 0) + return; + local_irq_save(flags); rec.ip = ip; @@ -49,6 +54,7 @@ static void notrace pstore_ftrace_call(unsigned long ip, psinfo->write(&record); local_irq_restore(flags); + ftrace_test_recursion_unlock(bit); } static struct ftrace_ops pstore_ftrace_ops __read_mostly = { |