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

From: Dan Carpenter
Date: Wed Nov 08 2023 - 01:48:50 EST


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?

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 }

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