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Fri, 14 Jun 2024 22:20:41 +0200 Message-ID: <083cd51b-06d8-4618-8517-a2bc2fa31554@web.de> Date: Fri, 14 Jun 2024 22:20:38 +0200 Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Hao Ge , linux-sound@vger.kernel.org, Jaroslav Kysela , Liam Girdwood , Mark Brown , Shenghao Ding , Takashi Iwai Cc: LKML , Colin Ian King References: <20240614024116.22130-1-hao.ge@linux.dev> Subject: Re: [PATCH] ASoc: PCM6240: Fix a null pointer dereference in pcmdevice_i2c_probe Content-Language: en-GB From: Markus Elfring In-Reply-To: <20240614024116.22130-1-hao.ge@linux.dev> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:XOJM/qaDGjcj4FvHjrKztjXIoneCDYiYIfC8036DqTPH0JKDqDQ dQHpox1P/5oxCdzAa8mGSlqpkyNqfGlxkDVfllKh/5aTX0+uj+7l1G6aLloHN6tvJa5VFF0 Y4rJNLHeW0KEQ+bO6XFPQXWqxr+g9eMu/nhMmydAQoRROyB/nYuGKZpq7v0fPBiuh9JqkoQ 3DED8GayWJS8AIBTPAi7w== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:2cv1dvyzcOM=;prvPWqHN9aM9/tNDwq0/vd1heIP 2K9yrELvlf4JHKfNAKV4hED4qIGbVV7u7fZ7yiz8vQHme5l8fpcQ7FJNV8gG05hYyOnYgHY/d fJU1t34aQawC1VB22IuU6Zr+6JdWVBLmRJYBGRSTUNtw3K11lcDxFgYmQMPnqlG/LPVpPoIWx T86sI8SsAk+IwTqEbBBF60DiSoTx+GrygVkkP4M2WGxIohOqNFJPeWNbWlUEWQ2n0/btviuaI jqo4+cSwFUzagWweEF9MGNhw3t3wNwrWka0m8gsMplnFzW6Gv8rAWlVEATrEn3Xub4SN6Tmd3 ijNuilMaeRqSYLXmhXDuSL9qpcU3rT9c09KBLvWuJV34Ss3bdZeP0ffZG1k+29p1AwezioD9z cNopnj4xhVPhutKw3pk88/YpbTI3tUcKGMMuuSmUNyNtM/rehSE24VpCBPzdRlbpkJrlvl9/5 OV4eyDRGHElWi0FFVi1PdaW4o0fmd0MNZHJPEE6l+jbBslIWsNiAA34c3iZT2KCyJI4qEZqn0 62LQRsEKMAS8cnMbrWzAOxynYyyaTTunZFwVaHxW8NR3VqPJmBVDqUDGf31EfNDtuk/PoidFk XqoJLRpXvbGvd0JshL/Gy/wANdjEum78YZMbFIlVQ4+cDh581tMgWZD6WoSw9hDbaH5lTTDMc mEzOggmTTMnhgxIyRTzv3Dg7roAkkqwSMX724FDWO86Y59ZxLtRLH/a0/G/3BmsDLJn6R6J1R 0uzMCyPwY5b0myLO2wU4BViCwuV/oHzbvg4drdFX94+yYyTrYuCbI1bCqfcIe+hAD7OGkboqm tdtVOHU0cshReS2TJrjEZeE7T58w2Z5X5hJ4is3OOJJ/8= > When devm_kzalloc return NULL,we return -ENOMEM directly to This information fits to a coding style advice. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Do= cumentation/process/coding-style.rst?h=3Dv6.10-rc3#n532 > avoid a null pointer that call pcmdevice_remove which will > perform some operations on the members of the pcm_dev; You pointed in an improvable way out that the label =E2=80=9Cout=E2=80=9D = was questionable after the assignment of a well-known error code at the beginning. https://elixir.bootlin.com/linux/v6.10-rc3/source/sound/soc/codecs/pcm6240= .c#L2077 Can a wording approach (like the following) be a better change description= ? The value =E2=80=9C-ENOMEM=E2=80=9D was assigned to the local variable = =E2=80=9Cret=E2=80=9D in one if branch after a devm_kzalloc() call failed at the beginning. This error code will trigger then a pcmdevice_remove() call with a passed null pointer so that an undesirable dereference will be performed. Thus return the appropriate error code directly. Can a summary phrase like =E2=80=9CReturn directly after a failed devm_kza= lloc() in pcmdevice_i2c_probe()=E2=80=9D be also helpful? Regards, Markus