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bh=fm2v9rBCIXUzUrmt72RQoSJ2B3nGVKZtSeUnw7U71lE=; b=t+4ylqAFKKKS0Fnxd2Xu9iu32YKM1NnfpW/+0pHS+0au0HgBiFNy0Nt5gJOF5e0ZZffY1W 3YtmvYAJ/N0zUs4rG8UZ2K0BbT2u5anICCo2o9pmFvPTFfiigpDKyt/V5WNwzf+Q6w1DcP 2pzowlBtvIlVPRgs+dmVQtRmC9wIn2rd7cFioiSwVw4YOgScPpThKijTVUxforFFrHWp5j 8zdK2Tgt5Yj1eteg/AhnlUtU3nUGoVlAhpX9XdV3ibv6lGG+vXrSkQfH5Wz4tf9bGrHQtO A3Y+Rk35j8GdzGT422e0D1Moui+/gU1CKuVizagTVQ9sbKPSYkzMq423VC5Ypg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1751877882; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=fm2v9rBCIXUzUrmt72RQoSJ2B3nGVKZtSeUnw7U71lE=; b=DXNsjw1Rz8o3UEgW2ia+AqFrm41ZxPUtMXbKupeV+oHgS9fcSLpCgmQJtAf+k+HGPO3ImH 7+CcNj2HvdpaZdBw== From: Sebastian Andrzej Siewior To: Yeoreum Yun Cc: glider@google.com, andreyknvl@gmail.com, dvyukov@google.com, vincenzo.frascino@arm.com, akpm@linux-foundation.org, clrkwllms@kernel.org, rostedt@goodmis.org, byungchul@sk.com, max.byungchul.park@gmail.com, ysk@kzalloc.com, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH v2] kasan: remove kasan_find_vm_area() to prevent possible deadlock Message-ID: <20250707084440.9hrE23w0@linutronix.de> References: <20250703181018.580833-1-yeoreum.yun@arm.com> <20250707083034.VXPTwRh2@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 1814E1C0007 X-Stat-Signature: cj844yfgssmop8x6g4iimtwofepqux7f X-Rspam-User: X-HE-Tag: 1751877883-597806 X-HE-Meta: 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 BQK+co2o UOj2/EQtPqfYTwHx6/24R7wpvuFbR/pEqJnz33FNVRLWLnoUA1lfPUM3Zk3FElWhoR9vNwtx5rpwtquxsaYpN/te4dlj3gI8tBzsNxvOMGdLTQHOIRmK6vKSKi/XytjGKInSpk7PAh2URW3OhHDsdBNiJICpAFhGKSgOUgmj0l1xc3CYk2UQWLIuzJVkzXsFsYvHLpSr0cNGDVJXXbcSzWPOCw3uoikm1gz4hy5eqTxaYg7o7HDvfkOXgrmkRwwC5tK6Zz/r+tAUptYo4//Vq9b27U9JvBVJk3/ozzLX7TQ5njayM5ktlstlcpEzh+t5A9DYiN6SBsJ1BzOl7KhLPqs/idkCdhRAKX8v4FdgbJ/m8Vszi9SbJsmpRol0miowHqllvJf7PPJItp8M= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2025-07-07 09:33:54 [+0100], Yeoreum Yun wrote: > Hi Sebastian, Hi, > > what is DEPT? > > Please check the below patchset: > https://lore.kernel.org/all/20250519091826.19752-1-byungchul@sk.com/ Thank you. Would lockdep see this if check_region_inline() would have something like (minus missing exports, just illustrate the idea) diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c index d54e89f8c3e76..c74e8e0863723 100644 --- a/mm/kasan/generic.c +++ b/mm/kasan/generic.c @@ -171,6 +171,11 @@ static __always_inline bool check_region_inline(const void *addr, if (unlikely(size == 0)) return true; + { + struct vmap_node *vn = vn = &vmap_nodes[0]; + might_lock(vn->busy.lock); + } + if (unlikely(addr + size < addr)) return !kasan_report(addr, size, write, ret_ip); ? Just to understand if lockdep is missing something essential or if DEPT was simply enabled why this "bad" accessed occurred and was able to see the lock chain which otherwise stays invisible. > Thanks! Sebastian