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authorYeoreum Yun <yeoreum.yun@arm.com>2025-07-03 19:10:18 +0100
committerAndrew Morton <akpm@linux-foundation.org>2025-07-09 21:07:54 -0700
commit6ee9b3d84775944fb8c8a447961cd01274ac671c (patch)
treecb1db3402dc0d6ad943f353386745559e607ce97
parente6d3e653b084f003977bf2e33820cb84d2e4541f (diff)
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>
-rw-r--r--mm/kasan/report.c45
1 files changed, 2 insertions, 43 deletions
diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index 8357e1a33699..b0877035491f 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -370,36 +370,6 @@ static inline bool init_task_stack_addr(const void *addr)
sizeof(init_thread_union.stack));
}
-/*
- * This function is invoked with report_lock (a raw_spinlock) held. A
- * PREEMPT_RT kernel cannot call find_vm_area() as it will acquire a sleeping
- * rt_spinlock.
- *
- * For !RT kernel, the PROVE_RAW_LOCK_NESTING config option will print a
- * lockdep warning for this raw_spinlock -> spinlock dependency. This config
- * option is enabled by default to ensure better test coverage to expose this
- * kind of RT kernel problem. This lockdep splat, however, can be suppressed
- * by using DEFINE_WAIT_OVERRIDE_MAP() if it serves a useful purpose and the
- * invalid PREEMPT_RT case has been taken care of.
- */
-static inline struct vm_struct *kasan_find_vm_area(void *addr)
-{
- static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEEP);
- struct vm_struct *va;
-
- if (IS_ENABLED(CONFIG_PREEMPT_RT))
- return NULL;
-
- /*
- * Suppress lockdep warning and fetch vmalloc area of the
- * offending address.
- */
- lock_map_acquire_try(&vmalloc_map);
- va = find_vm_area(addr);
- lock_map_release(&vmalloc_map);
- return va;
-}
-
static void print_address_description(void *addr, u8 tag,
struct kasan_report_info *info)
{
@@ -429,19 +399,8 @@ static void print_address_description(void *addr, u8 tag,
}
if (is_vmalloc_addr(addr)) {
- struct vm_struct *va = kasan_find_vm_area(addr);
-
- if (va) {
- pr_err("The buggy address belongs to the virtual mapping at\n"
- " [%px, %px) created by:\n"
- " %pS\n",
- va->addr, va->addr + va->size, va->caller);
- pr_err("\n");
-
- page = vmalloc_to_page(addr);
- } else {
- pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
- }
+ pr_err("The buggy address %px belongs to a vmalloc virtual mapping\n", addr);
+ page = vmalloc_to_page(addr);
}
if (page) {