tree: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git dio-mem-align head: 3d6ef82805958611e8ffa0a901c014b6f066c3e6 commit: 446db6bc49cd5c4a77daffbbcbe0cf69ff7a62e0 [1/3] fs: relax memory alignment restriction for O_DIRECT config: x86_64-randconfig-m001-20210211 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; Reported-by: Dan Carpenter <dan.carpenter(a)oracle.com&gt; smatch warnings: fs/direct-io.c:1177 do_blockdev_direct_IO() warn: variable dereferenced before check 'bdev' (see line 1132) vim +/bdev +1177 fs/direct-io.c 65dd2aa90aa17a Andi Kleen 2012-01-12 1125 static inline ssize_t 17f8c842d24ac0 Omar Sandoval 2015-03-16 1126 do_blockdev_direct_IO(struct kiocb *iocb, struct inode *inode, 17f8c842d24ac0 Omar Sandoval 2015-03-16 1127 struct block_device *bdev, struct iov_iter *iter, c8b8e32d700fe9 Christoph Hellwig 2016-04-07 1128 get_block_t get_block, dio_iodone_t end_io, facd07b07d2a79 Josef Bacik 2010-05-23 1129 dio_submit_t submit_io, int flags) ^1da177e4c3f41 Linus Torvalds 2005-04-16 1130 { 6aa7de059173a9 Mark Rutland 2017-10-23 1131 unsigned i_blkbits = READ_ONCE(inode->i_blkbits); 446db6bc49cd5c Jens Axboe 2021-02-11 @1132 struct request_queue *q = bdev_get_queue(bdev); ^^^^ Dereferenced inside the function (I didn't double check. #trustTheMachine) ab73857e354ab9 Linus Torvalds 2012-11-29 1133 unsigned blkbits = i_blkbits; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1134 unsigned blocksize_mask = (1 << blkbits) - 1; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1135 ssize_t retval = -EINVAL; 1c0ff0f1bdeb18 Nikolay Borisov 2018-04-05 1136 const size_t count = iov_iter_count(iter); c8b8e32d700fe9 Christoph Hellwig 2016-04-07 1137 loff_t offset = iocb->ki_pos; 1c0ff0f1bdeb18 Nikolay Borisov 2018-04-05 1138 const loff_t end = offset + count; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1139 struct dio *dio; eb28be2b4c0a06 Andi Kleen 2011-08-01 1140 struct dio_submit sdio = { 0, }; 847cc6371ba820 Andi Kleen 2011-08-01 1141 struct buffer_head map_bh = { 0, }; 647d1e4c523576 Fengguang Wu 2012-08-09 1142 struct blk_plug plug; ^1da177e4c3f41 Linus Torvalds 2005-04-16 1143 65dd2aa90aa17a Andi Kleen 2012-01-12 1144 /* 65dd2aa90aa17a Andi Kleen 2012-01-12 1145 * Avoid references to bdev if not absolutely needed to give 65dd2aa90aa17a Andi Kleen 2012-01-12 1146 * the early prefetch in the caller enough time. 65dd2aa90aa17a Andi Kleen 2012-01-12 1147 */ ^1da177e4c3f41 Linus Torvalds 2005-04-16 1148 f9b5570d7fdedf Christoph Hellwig 2011-06-24 1149 /* watch out for a 0 len io from a tricksy fs */ 1c0ff0f1bdeb18 Nikolay Borisov 2018-04-05 1150 if (iov_iter_rw(iter) == READ && !count) f9b5570d7fdedf Christoph Hellwig 2011-06-24 1151 return 0; f9b5570d7fdedf Christoph Hellwig 2011-06-24 1152 6e8267f532a171 Andi Kleen 2011-08-01 1153 dio = kmem_cache_alloc(dio_cache, GFP_KERNEL); ^1da177e4c3f41 Linus Torvalds 2005-04-16 1154 if (!dio) 46d716025a228d Gabriel Krisman Bertazi 2020-10-08 1155 return -ENOMEM; 23aee091d804ef Jeff Moyer 2009-12-15 1156 /* 23aee091d804ef Jeff Moyer 2009-12-15 1157 * Believe it or not, zeroing out the page array caused a .5% 23aee091d804ef Jeff Moyer 2009-12-15 1158 * performance regression in a database benchmark. So, we take 23aee091d804ef Jeff Moyer 2009-12-15 1159 * care to only zero out what's needed. 23aee091d804ef Jeff Moyer 2009-12-15 1160 */ 23aee091d804ef Jeff Moyer 2009-12-15 1161 memset(dio, 0, offsetof(struct dio, pages)); ^1da177e4c3f41 Linus Torvalds 2005-04-16 1162 5fe878ae7f82fb Christoph Hellwig 2009-12-15 1163 dio->flags = flags; 0a9164cb7ff32d Gabriel Krisman Bertazi 2020-10-08 1164 if (dio->flags & DIO_LOCKING && iov_iter_rw(iter) == READ) { 5fe878ae7f82fb Christoph Hellwig 2009-12-15 1165 /* will be released by direct_io_worker */ 5955102c9984fa Al Viro 2016-01-22 1166 inode_lock(inode); df2d6f26586f12 Christoph Hellwig 2011-06-24 1167 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 1168 74cedf9b6c603f Jan Kara 2015-11-30 1169 /* Once we sampled i_size check for reads beyond EOF */ 74cedf9b6c603f Jan Kara 2015-11-30 1170 dio->i_size = i_size_read(inode); 74cedf9b6c603f Jan Kara 2015-11-30 1171 if (iov_iter_rw(iter) == READ && offset >= dio->i_size) { 2d4594acbf6d8f Al Viro 2015-12-08 1172 retval = 0; 46d716025a228d Gabriel Krisman Bertazi 2020-10-08 1173 goto fail_dio; 74cedf9b6c603f Jan Kara 2015-11-30 1174 } 74cedf9b6c603f Jan Kara 2015-11-30 1175 446db6bc49cd5c Jens Axboe 2021-02-11 1176 if (offset & blocksize_mask) { 41b21af388f94b Gabriel Krisman Bertazi 2020-10-08 @1177 if (bdev) ^^^^ Hopefully this check can be removed? We would have crashed by this point. 41b21af388f94b Gabriel Krisman Bertazi 2020-10-08 1178 blkbits = blksize_bits(bdev_logical_block_size(bdev)); 41b21af388f94b Gabriel Krisman Bertazi 2020-10-08 1179 blocksize_mask = (1 << blkbits) - 1; 446db6bc49cd5c Jens Axboe 2021-02-11 1180 if (offset & blocksize_mask) 41b21af388f94b Gabriel Krisman Bertazi 2020-10-08 1181 goto fail_dio; 41b21af388f94b Gabriel Krisman Bertazi 2020-10-08 1182 } --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org