kasan: remove kasan_find_vm_area() to prevent possible deadlock
authorYeoreum Yun <yeoreum.yun@arm.com>
Thu, 3 Jul 2025 18:10:18 +0000 (19:10 +0100)
committerAndrew Morton <akpm@linux-foundation.org>
Thu, 10 Jul 2025 04:07:54 +0000 (21:07 -0700)
commit6ee9b3d84775944fb8c8a447961cd01274ac671c
treecb1db3402dc0d6ad943f353386745559e607ce97
parente6d3e653b084f003977bf2e33820cb84d2e4541f
kasan: remove kasan_find_vm_area() to prevent possible deadlock

find_vm_area() couldn't be called in atomic_context.  If find_vm_area() is
called to reports vm area information, kasan can trigger deadlock like:

CPU0                                CPU1
vmalloc();
 alloc_vmap_area();
  spin_lock(&vn->busy.lock)
                                    spin_lock_bh(&some_lock);
   <interrupt occurs>
   <in softirq>
   spin_lock(&some_lock);
                                    <access invalid address>
                                    kasan_report();
                                     print_report();
                                      print_address_description();
                                       kasan_find_vm_area();
                                        find_vm_area();
                                         spin_lock(&vn->busy.lock) // deadlock!

To prevent possible deadlock while kasan reports, remove kasan_find_vm_area().

Link: https://lkml.kernel.org/r/20250703181018.580833-1-yeoreum.yun@arm.com
Fixes: c056a364e954 ("kasan: print virtual mapping info in reports")
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reported-by: Yunseong Kim <ysk@kzalloc.com>
Reviewed-by: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/kasan/report.c