From 2cd896a5e86fc326bda8614b96c0401dcc145868 Mon Sep 17 00:00:00 2001 From: Ritesh Harjani Date: Wed, 9 Sep 2020 08:44:25 +0530 Subject: [PATCH] block: Set same_page to false in __bio_try_merge_page if ret is false If we hit the UINT_MAX limit of bio->bi_iter.bi_size and so we are anyway not merging this page in this bio, then it make sense to make same_page also as false before returning. Without this patch, we hit below WARNING in iomap. This mostly happens with very large memory system and / or after tweaking vm dirty threshold params to delay writeback of dirty data. WARNING: CPU: 18 PID: 5130 at fs/iomap/buffered-io.c:74 iomap_page_release+0x120/0x150 CPU: 18 PID: 5130 Comm: fio Kdump: loaded Tainted: G W 5.8.0-rc3 #6 Call Trace: __remove_mapping+0x154/0x320 (unreliable) iomap_releasepage+0x80/0x180 try_to_release_page+0x94/0xe0 invalidate_inode_page+0xc8/0x110 invalidate_mapping_pages+0x1dc/0x540 generic_fadvise+0x3c8/0x450 xfs_file_fadvise+0x2c/0xe0 [xfs] vfs_fadvise+0x3c/0x60 ksys_fadvise64_64+0x68/0xe0 sys_fadvise64+0x28/0x40 system_call_exception+0xf8/0x1c0 system_call_common+0xf0/0x278 Fixes: cc90bc68422 ("block: fix "check bi_size overflow before merge"") Reported-by: Shivaprasad G Bhat Suggested-by: Christoph Hellwig Signed-off-by: Anju T Sudhakar Signed-off-by: Ritesh Harjani Reviewed-by: Ming Lei Reviewed-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/bio.c b/block/bio.c index a9931f23d933..e865ea55b9f9 100644 --- a/block/bio.c +++ b/block/bio.c @@ -879,8 +879,10 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page, struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; if (page_is_mergeable(bv, page, len, off, same_page)) { - if (bio->bi_iter.bi_size > UINT_MAX - len) + if (bio->bi_iter.bi_size > UINT_MAX - len) { + *same_page = false; return false; + } bv->bv_len += len; bio->bi_iter.bi_size += len; return true;