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[46.53.134.148]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48e5382a327sm224564925e9.0.2026.05.07.06.49.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 07 May 2026 06:49:57 -0700 (PDT) Date: Thu, 7 May 2026 16:52:19 +0300 From: Alexey Dobriyan To: Danilo Krummrich Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-fsdevel@vger.kernel.org, driver-core@lists.linux.dev Subject: Re: [PATCH] sysfs: upgrade OOB write by buggy .show hook into WARNing Message-ID: <7bc745f1-a8fb-4bfd-8b85-657333a1bbf1@p183> References: <5f794f46-5afd-405c-9747-76f2c95d4598@p183> <3cc3e8c6-c6e8-4625-a88f-f5708b935dab@p183> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Thu, May 07, 2026 at 11:28:29AM +0200, Danilo Krummrich wrote: > (Cc: driver-core) > > On Thu May 7, 2026 at 11:01 AM CEST, Alexey Dobriyan wrote: > > Buggy .show hook will get just 1 line of dmesg: > > > > fill_read_buffer: ext4_attr_show+0x0/0x600 returned bad count > > > > It may or may not oops later in some unrelated process. > > > > But buggy .show hook most likely is corrupting random memory past sysfs > > buffer therefore deserving more. WARN, make it more visible and let > > QA machines panic earlier. > > > > Also, delete useless cast -- "count" is >=0 at this point. > > > > Signed-off-by: Alexey Dobriyan > > Reviewed-by: Danilo Krummrich > > NIT: This patch also cleans up the stale "fill_read_buffer:" prefix, and instead > points out the actual caller, which could be mentioned in the commit message -- > no need to resend for this though. Yes. WARN prints enough information to locate the bug, so stale function name just goes away.