The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x e30a0361b8515d424c73c67de1a43e45a13b8ba2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024121010-gladiator-streak-993a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From e30a0361b8515d424c73c67de1a43e45a13b8ba2 Mon Sep 17 00:00:00 2001 From: Jared Kangas jkangas@redhat.com Date: Tue, 19 Nov 2024 13:02:34 -0800 Subject: [PATCH] kasan: make report_lock a raw spinlock
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@redhat.com Fixes: 342a93247e08 ("locking/spinlock: Provide RT variant header: <linux/spinlock_rt.h>") Signed-off-by: Jared Kangas jkangas@redhat.com Cc: Alexander Potapenko glider@google.com Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Dmitry Vyukov dvyukov@google.com Cc: Vincenzo Frascino vincenzo.frascino@arm.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org
diff --git a/mm/kasan/report.c b/mm/kasan/report.c index 50fb19ad4388..3fe77a360f1c 100644 --- a/mm/kasan/report.c +++ b/mm/kasan/report.c @@ -201,7 +201,7 @@ static inline void fail_non_kasan_kunit_test(void) { }
#endif /* CONFIG_KUNIT */
-static DEFINE_SPINLOCK(report_lock); +static DEFINE_RAW_SPINLOCK(report_lock);
static void start_report(unsigned long *flags, bool sync) { @@ -212,7 +212,7 @@ 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"); }
@@ -222,7 +222,7 @@ static void end_report(unsigned long *flags, const void *addr, bool is_write) 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"); switch (kasan_arg_fault) {