From: Jan Höppner <hoeppner@linux.ibm.com> stable inclusion from stable-v5.10.115 commit 6e02c0413a93ee3195bd68f2166c6d1fbe21b73c category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5IZ9C Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit cd68c48ea15c85f1577a442dc4c285e112ff1b37 upstream. When reading unformatted tracks on ESE devices, the corresponding memory areas are simply set to zero for each segment. This is done incorrectly for blocksizes < 4096. There are two problems. First, the increment of dst is done using the counter of the loop (off), which is increased by blksize every iteration. This leads to a much bigger increment for dst as actually intended. Second, the increment of dst is done before the memory area is set to 0, skipping a significant amount of bytes of memory. This leads to illegal overwriting of memory and ultimately to a kernel panic. This is not a problem with 4k blocksize because blk_queue_max_segment_size is set to PAGE_SIZE, always resulting in a single iteration for the inner segment loop (bv.bv_len == blksize). The incorrectly used 'off' value to increment dst is 0 and the correct memory area is used. In order to fix this for blksize < 4k, increment dst correctly using the blksize and only do it at the end of the loop. Fixes: 5e2b17e712cf ("s390/dasd: Add dynamic formatting support for ESE volumes") Cc: stable@vger.kernel.org # v5.3+ Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com> Reviewed-by: Stefan Haberland <sth@linux.ibm.com> Link: https://lore.kernel.org/r/20220505141733.1989450-4-sth@linux.ibm.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Acked-by: Xie XiuQi <xiexiuqi@huawei.com> --- drivers/s390/block/dasd_eckd.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c index 59d469bddf3d..7749deb614d7 100644 --- a/drivers/s390/block/dasd_eckd.c +++ b/drivers/s390/block/dasd_eckd.c @@ -3228,12 +3228,11 @@ static int dasd_eckd_ese_read(struct dasd_ccw_req *cqr, struct irb *irb) cqr->proc_bytes = blk_count * blksize; return 0; } - if (dst && !skip_block) { - dst += off; + if (dst && !skip_block) memset(dst, 0, blksize); - } else { + else skip_block--; - } + dst += blksize; blk_count++; } } -- 2.20.1