This is a note to let you know that I've just added the patch titled
kasan: make report_lock a raw spinlock
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kasan-make-report_lock-a-raw-spinlock.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 464468fa29f9244613add91dd38810189c07b54b
Author: Jared Kangas <jkangas@xxxxxxxxxx>
Date: Tue Nov 19 13:02:34 2024 -0800
kasan: make report_lock a raw spinlock
[ Upstream commit e30a0361b8515d424c73c67de1a43e45a13b8ba2 ]
If PREEMPT_RT is enabled, report_lock is a sleeping spinlock and must not
be locked when IRQs are disabled. However, KASAN reports may be triggered
in such contexts. For example:
char *s = kzalloc(1, GFP_KERNEL);
kfree(s);
local_irq_disable();
char c = *s; /* KASAN report here leads to spin_lock() */
local_irq_enable();
Make report_spinlock a raw spinlock to prevent rescheduling when
PREEMPT_RT is enabled.
Link: https://lkml.kernel.org/r/20241119210234.1602529-1-jkangas@xxxxxxxxxx
Fixes: 342a93247e08 ("locking/spinlock: Provide RT variant header: <linux/spinlock_rt.h>")
Signed-off-by: Jared Kangas <jkangas@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Andrey Ryabinin <ryabinin.a.a@xxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 821cd12e8c8a7..6ad986c267b5e 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -173,7 +173,7 @@ static void update_kunit_status(bool sync)
static void update_kunit_status(bool sync) { }
#endif
-static DEFINE_SPINLOCK(report_lock);
+static DEFINE_RAW_SPINLOCK(report_lock);
static void start_report(unsigned long *flags, bool sync)
{
@@ -185,7 +185,7 @@ static void start_report(unsigned long *flags, bool sync)
lockdep_off();
/* Make sure we don't end up in loop. */
report_suppress_start();
- spin_lock_irqsave(&report_lock, *flags);
+ raw_spin_lock_irqsave(&report_lock, *flags);
pr_err("==================================================================\n");
}
@@ -195,7 +195,7 @@ static void end_report(unsigned long *flags, void *addr)
trace_error_report_end(ERROR_DETECTOR_KASAN,
(unsigned long)addr);
pr_err("==================================================================\n");
- spin_unlock_irqrestore(&report_lock, *flags);
+ raw_spin_unlock_irqrestore(&report_lock, *flags);
if (!test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
check_panic_on_warn("KASAN");
if (kasan_arg_fault == KASAN_ARG_FAULT_PANIC)
