On 12/22/2022 12:35 PM, shaozhengchao wrote: > > > -----Original Message----- > From: Arend van Spriel [mailto:arend.vanspriel@broadcom.com] > Sent: Thursday, December 22, 2022 7:00 PM > To: shaozhengchao ; Kalle Valo ; Sebastian Andrzej Siewior > Cc: netdev@vger.kernel.org; linux-wireless@vger.kernel.org; brcm80211-dev-list.pdl@broadcom.com; SHA-cyfmac-dev-list@infineon.com; davem@davemloft.net; edumazet@google.com; kuba@kernel.org; pabeni@redhat.com; aspriel@gmail.com; franky.lin@broadcom.com; hante.meuleman@broadcom.com; wright.feng@cypress.com; chi-hsien.lin@cypress.com; a.fatoum@pengutronix.de; alsi@bang-olufsen.dk; pieterpg@broadcom.com; dekim@broadcom.com; linville@tuxdriver.com; weiyongjun (A) ; yuehaibing > Subject: Re: [PATCH] wifi: brcmfmac: unmap dma buffer in brcmf_msgbuf_alloc_pktid() > > On 12/22/2022 9:52 AM, shaozhengchao wrote: >> >> >> On 2022/12/22 16:46, Kalle Valo wrote: >>> Sebastian Andrzej Siewior writes: >>> >>>> On 2022-12-21 18:33:06 [+0000], Kalle Valo wrote: >>>>> Zhengchao Shao wrote: >>>>> >>>>>> After the DMA buffer is mapped to a physical address, address is >>>>>> stored >>>>>> in pktids in brcmf_msgbuf_alloc_pktid(). Then, pktids is parsed in >>>>>> brcmf_msgbuf_get_pktid()/brcmf_msgbuf_release_array() to obtain >>>>>> physaddr >>>>>> and later unmap the DMA buffer. But when count is always equal to >>>>>> pktids->array_size, physaddr isn't stored in pktids and the DMA buffer >>>>>> will not be unmapped anyway. >>>>>> >>>>>> Fixes: 9a1bb60250d2 ("brcmfmac: Adding msgbuf protocol.") >>>>>> Signed-off-by: Zhengchao Shao >>>>> >>>>> Can someone review this? >>>> >>>> After looking at the code, that skb is mapped but not inserted into the >>>> ringbuffer in this condition. The function returns with an error and the >>>> caller will free that skb (or add to a list for later). Either way the >>>> skb remains mapped which is wrong. The unmap here is the right thing to >>>> do. >>>> >>>> Reviewed-by: Sebastian Andrzej Siewior >>> >>> Thanks for the review, very much appreciated. >>> >> >> Thank you very much. > >> Good catch. Has this path been observed or is this found by inspecting >> the code? Just curious. > >> Regards, >> Arend > > Hi Arend： > I review code and find the bug. Much appreciated. Regards, Arend > Zhengchao Shao