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AJvYcCWK+LGt4zMOtFRxN2Aifdw4oTbQcK7ChL4D0hw3FoVq4/0UROI02GMNFh/3cGAVtPIJ2lxXDOcnygC6N25a@vger.kernel.org X-Gm-Message-State: AOJu0Yx11zUh3FMfZCGLbTKtYThSbNmq7BwwzPBCffrkgChm3RuOp01A XxTdpQJCImEOgCpxzEEwaMVdLtwMibm3VyJj8KD2FThquqYozofy7K49k79KgkpIDEYmTe8kC8q k3wYB9dVMjEBvBp6pib9lqlTP+vZtl1fTuVtM2NiXilgH2ZrzuOhB1bAIG9c= X-Google-Smtp-Source: AGHT+IFOMgny6AZoeKClnUtWwvvWlBtfpV/YOGECAMlY6kCDL9+DCaNziVGkIJErsIkHssksFdIXB1lS9Df2ZzUnKrqroofJYo46 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:230a:b0:425:7788:871 with SMTP id e9e14a558f8ab-42875791953mr109399565ab.12.1759084940438; Sun, 28 Sep 2025 11:42:20 -0700 (PDT) Date: Sun, 28 Sep 2025 11:42:20 -0700 In-Reply-To: <20250928132927.3672537-1-ming.lei@redhat.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68d9818c.a00a0220.102ee.002d.GAE@google.com> Subject: [syzbot ci] Re: loop: improve loop aio perf by IOCB_NOWAIT From: syzbot ci To: axboe@kernel.dk, dchinner@redhat.com, hch@lst.de, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, ming.lei@redhat.com, mpatocka@redhat.com, zhaoyang.huang@unisoc.com Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v1] loop: improve loop aio perf by IOCB_NOWAIT https://lore.kernel.org/all/20250928132927.3672537-1-ming.lei@redhat.com * [PATCH V4 1/6] loop: add helper lo_cmd_nr_bvec() * [PATCH V4 2/6] loop: add helper lo_rw_aio_prep() * [PATCH V4 3/6] loop: add lo_submit_rw_aio() * [PATCH V4 4/6] loop: move command blkcg/memcg initialization into loop_queue_work * [PATCH V4 5/6] loop: try to handle loop aio command via NOWAIT IO first * [PATCH V4 6/6] loop: add hint for handling aio via IOCB_NOWAIT and found the following issue: WARNING in lo_submit_rw_aio Full report is available here: https://ci.syzbot.org/series/0ffdb6b4-a5fe-48da-9473-d2a926e780bd *** WARNING in lo_submit_rw_aio tree: torvalds URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux base: 07e27ad16399afcd693be20211b0dfae63e0615f arch: amd64 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 config: https://ci.syzbot.org/builds/3aba003b-2400-4e88-9a31-c09ab4e41a84/config C repro: https://ci.syzbot.org/findings/dc97454c-d87b-41f5-a44a-7182e666cfd5/c_repro syz repro: https://ci.syzbot.org/findings/dc97454c-d87b-41f5-a44a-7182e666cfd5/syz_repro ------------[ cut here ]------------ WARNING: CPU: 0 PID: 5958 at drivers/block/loop.c:907 loop_inc_blocking_writes drivers/block/loop.c:907 [inline] WARNING: CPU: 0 PID: 5958 at drivers/block/loop.c:907 loop_queue_work+0xb3b/0xc30 drivers/block/loop.c:1005 Modules linked in: CPU: 0 UID: 0 PID: 5958 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:loop_inc_blocking_writes drivers/block/loop.c:907 [inline] RIP: 0010:loop_queue_work+0xb3b/0xc30 drivers/block/loop.c:1005 Code: 33 bf 08 00 00 00 4c 89 ea e8 c1 89 7e fb 4c 89 f7 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d e9 cb 87 71 05 e8 26 36 b4 fb 90 <0f> 0b 90 e9 4e fe ff ff e8 18 36 b4 fb 48 83 c5 18 48 89 e8 48 c1 RSP: 0018:ffffc9000340ef38 EFLAGS: 00010093 RAX: ffffffff860b776a RBX: ffff88802187c000 RCX: ffff88810cee3980 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000681dc4 R12: ffff88802187c158 R13: ffff88802187c110 R14: ffff888021989460 R15: ffff888021989418 FS: 00007f649c5a4c80(0000) GS:ffff8880b8612000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000056520d53f000 CR3: 0000000109e48000 CR4: 00000000000006f0 Call Trace: lo_submit_rw_aio+0x493/0x620 drivers/block/loop.c:441 lo_rw_aio_nowait drivers/block/loop.c:508 [inline] loop_queue_rq+0x64d/0x840 drivers/block/loop.c:2026 __blk_mq_issue_directly block/blk-mq.c:2695 [inline] blk_mq_request_issue_directly+0x3c1/0x710 block/blk-mq.c:2782 blk_mq_issue_direct+0x2a0/0x660 block/blk-mq.c:2803 blk_mq_dispatch_queue_requests+0x621/0x800 block/blk-mq.c:2878 blk_mq_flush_plug_list+0x432/0x550 block/blk-mq.c:2961 __blk_flush_plug+0x3d3/0x4b0 block/blk-core.c:1220 blk_finish_plug+0x5e/0x90 block/blk-core.c:1247 read_pages+0x3b2/0x580 mm/readahead.c:173 page_cache_ra_unbounded+0x6b0/0x7b0 mm/readahead.c:297 do_page_cache_ra mm/readahead.c:327 [inline] force_page_cache_ra mm/readahead.c:356 [inline] page_cache_sync_ra+0x3b9/0xb10 mm/readahead.c:572 filemap_get_pages+0x43c/0x1ea0 mm/filemap.c:2603 filemap_read+0x3f6/0x11a0 mm/filemap.c:2712 blkdev_read_iter+0x30a/0x440 block/fops.c:852 new_sync_read fs/read_write.c:491 [inline] vfs_read+0x55a/0xa30 fs/read_write.c:572 ksys_read+0x145/0x250 fs/read_write.c:715 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f649c116b6a Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffd6597a888 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000040000 RCX: 00007f649c116b6a RDX: 0000000000040000 RSI: 000056520d500438 RDI: 0000000000000009 RBP: 0000000000040000 R08: 000056520d500410 R09: 0000000000000010 R10: 0000000000004011 R11: 0000000000000246 R12: 000056520d500410 R13: 000056520d500428 R14: 000056520d3cf9c8 R15: 000056520d3cf970 *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com.