Re: [PATCH v3 3/4] bus: mhi: host: Avoid processing buffer and event of a disable channel

[Qiang Yu]

On 11/8/2023 2:48 PM, Dan Carpenter wrote:
> Hi Qiang,
>
> kernel test robot noticed the following build warnings:
>
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Qiang-Yu/bus-mhi-host-Add-spinlock-to-protect-WP-access-when-queueing-TREs/20231107-151918
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/mani/mhi.git mhi-next
> patch link:    https://lore.kernel.org/r/1699341365-47737-4-git-send-email-quic_qianyu%40quicinc.com
> patch subject: [PATCH v3 3/4] bus: mhi: host: Avoid processing buffer and event of a disable channel
> config: x86_64-randconfig-161-20231107 (https://download.01.org/0day-ci/archive/20231108/202311080155.MiyREgoQ-lkp@xxxxxxxxx/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce: (https://download.01.org/0day-ci/archive/20231108/202311080155.MiyREgoQ-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> | Closes: https://lore.kernel.org/r/202311080155.MiyREgoQ-lkp@xxxxxxxxx/
>
> smatch warnings:
> drivers/bus/mhi/host/main.c:1257 mhi_gen_tre() warn: inconsistent returns '&mhi_chan->lock'.
>
> vim +1257 drivers/bus/mhi/host/main.c
>
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1204  int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1205  			struct mhi_buf_info *info, enum mhi_flags flags)
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1206  {
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1207  	struct mhi_ring *buf_ring, *tre_ring;
> 84f5f31f110e5e drivers/bus/mhi/host/main.c Manivannan Sadhasivam 2022-03-01  1208  	struct mhi_ring_element *mhi_tre;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1209  	struct mhi_buf_info *buf_info;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1210  	int eot, eob, chain, bei;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1211  	int ret;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1212
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1213  	/* Protect accesses for reading and incrementing WP */
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1214  	write_lock_bh(&mhi_chan->lock);
> 6025cde6ecb13c drivers/bus/mhi/host/main.c Qiang Yu              2023-11-07  1215  	if (mhi_chan->ch_state != MHI_CH_STATE_ENABLED)
> 6025cde6ecb13c drivers/bus/mhi/host/main.c Qiang Yu              2023-11-07  1216  		return -EINVAL;
>
> This looks like two people submitted patches on the same day?
> We should unlock before returning?
Yes, we should unlock before return, will change in next version patch. 
Thank you.
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1217
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1218  	buf_ring = &mhi_chan->buf_ring;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1219  	tre_ring = &mhi_chan->tre_ring;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1220
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1221  	buf_info = buf_ring->wp;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1222  	WARN_ON(buf_info->used);
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1223  	buf_info->pre_mapped = info->pre_mapped;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1224  	if (info->pre_mapped)
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1225  		buf_info->p_addr = info->p_addr;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1226  	else
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1227  		buf_info->v_addr = info->v_addr;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1228  	buf_info->cb_buf = info->cb_buf;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1229  	buf_info->wp = tre_ring->wp;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1230  	buf_info->dir = mhi_chan->dir;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1231  	buf_info->len = info->len;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1232
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1233  	if (!info->pre_mapped) {
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1234  		ret = mhi_cntrl->map_single(mhi_cntrl, buf_info);
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1235  		if (ret) {
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1236  			write_unlock_bh(&mhi_chan->lock);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1237  			return ret;
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1238  		}
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1239  	}
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1240
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1241  	eob = !!(flags & MHI_EOB);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1242  	eot = !!(flags & MHI_EOT);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1243  	chain = !!(flags & MHI_CHAIN);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1244  	bei = !!(mhi_chan->intmod);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1245
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1246  	mhi_tre = tre_ring->wp;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1247  	mhi_tre->ptr = MHI_TRE_DATA_PTR(buf_info->p_addr);
> cd116318803f5e drivers/bus/mhi/core/main.c Hemant Kumar          2020-05-21  1248  	mhi_tre->dword[0] = MHI_TRE_DATA_DWORD0(info->len);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1249  	mhi_tre->dword[1] = MHI_TRE_DATA_DWORD1(bei, eot, eob, chain);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1250
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1251  	/* increment WP */
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1252  	mhi_add_ring_element(mhi_cntrl, tre_ring);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1253  	mhi_add_ring_element(mhi_cntrl, buf_ring);
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1254
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1255  	write_unlock_bh(&mhi_chan->lock);
> da05b5d43f483c drivers/bus/mhi/host/main.c Bhaumik Bhatt         2023-11-07  1256
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20 @1257  	return 0;
> 189ff97cca53e3 drivers/bus/mhi/core/main.c Manivannan Sadhasivam 2020-02-20  1258  }