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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2020-11-05 21:32:39 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-11-06 08:33:23 -0500
commit6cdf941871ec9cb1cf03227038a45a73afd8dc9a (patch)
treedb2e7e2c3b1088b873fb25076d55331ec3564401 /fs/pstore
parentda5afbeb1724609996ca7bb4fbce2cd104c95914 (diff)
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.c6
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 = {