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Fri, 04 Jul 2025 05:41:57 -0700 (PDT) Message-ID: <37b96f5f-d79e-47bd-9616-b6c8905bc984@gmail.com> Date: Fri, 4 Jul 2025 14:40:39 +0200 Precedence: bulk X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] kasan: remove kasan_find_vm_area() to prevent possible deadlock To: Yeoreum Yun , glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, akpm@linux-foundation.org, bigeasy@linutronix.de, clrkwllms@kernel.org, rostedt@goodmis.org, byungchul@sk.com, max.byungchul.park@gmail.com, ysk@kzalloc.com Cc: kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev References: <20250703181018.580833-1-yeoreum.yun@arm.com> Content-Language: en-US From: Andrey Ryabinin In-Reply-To: <20250703181018.580833-1-yeoreum.yun@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/3/25 8:10 PM, Yeoreum Yun wrote: > 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); > > > spin_lock(&some_lock); > > 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(). > > Fixes: c056a364e954 ("kasan: print virtual mapping info in reports") > Reported-by: Yunseong Kim > Signed-off-by: Yeoreum Yun Reviewed-by: Andrey Ryabinin