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AHgh+RoGIqrn2m53wtQvWToGEXVozz8hgphgwnikyLAdkYqThKoOVH/ti0d3LQu+CtwecZs6GLqe60Ab@vger.kernel.org X-Gm-Message-State: AOJu0YyBkLhoI9t+KebIq05fJWQcg7TJ1rcYnghBXvaHlc1HHCVxK1zs ll3lST/awufNwUiEa9wBW94NYl6dylnYDVmDOoUOEclyKAn1ngfbco1pZz9fGamc5q+SSQZlbm0 nJ/KR3cbOCqHHS7GQFeV+1yHcZPe0C9ZfUOfO8IjI3DwH45IsTbAsuvREbjY= Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1385:b0:4a3:d383:b3ea with SMTP id 5614622812f47-4ab6a24e0cdmr4071021b6e.27.1785049681809; Sun, 26 Jul 2026 00:08:01 -0700 (PDT) Date: Sun, 26 Jul 2026 00:08:01 -0700 In-Reply-To: <20260724123037.3004560-1-yukuai@kernel.org> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a65b251.073198cf.94f0f.0024.GAE@google.com> Subject: [syzbot ci] Re: blk-cgroup: protect blkgs with blkcg_mutex From: syzbot ci To: axboe@kernel.dk, cengku@gmail.com, cgroups@vger.kernel.org, dongsheng.yang@linux.dev, hch@lst.de, josef@toxicpanda.com, linux-block@vger.kernel.org, ming.lei@redhat.com, nilay@linux.ibm.com, tj@kernel.org, yukuai@fygo.io, yukuai@kernel.org Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v2] blk-cgroup: protect blkgs with blkcg_mutex https://lore.kernel.org/all/20260724123037.3004560-1-yukuai@kernel.org * [RFC PATCH v2 1/8] block: associate blkg in submit_bio instead of bio_set_dev * [RFC PATCH v2 2/8] blk-throttle: protect throttle state with td lock * [RFC PATCH v2 3/8] blk-cgroup: protect blkgs with blkcg_mutex * [RFC PATCH v2 4/8] blk-cgroup: remove blkg radix tree preloading * [RFC PATCH v2 5/8] blk-cgroup: allocate blkgs in blkg_create * [RFC PATCH v2 6/8] blk-cgroup: share blkg creation between lookup and config prep * [RFC PATCH v2 7/8] bfq: avoid blkg lookup from locked cgroup update * [RFC PATCH v2 8/8] block: fail nowait bio submit if blkg allocation can't sleep and found the following issue: general protection fault in blkcg_punt_bio_submit Full report is available here: https://ci.syzbot.org/series/eece31b0-1f5d-4840-8a12-407d9a4d1c57 *** general protection fault in blkcg_punt_bio_submit tree: axboe URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/axboe/linux.git base: 093fbffe03f5c1bb9c10a9e5aa65b23250844403 arch: amd64 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 config: https://ci.syzbot.org/builds/2cc06765-4cf6-4329-9c0a-9fe326a5338e/config syz repro: https://ci.syzbot.org/findings/38efdd1d-4179-4903-8ade-04afbce263b2/syz_repro Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037] CPU: 0 UID: 0 PID: 26 Comm: kworker/u9:0 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 Workqueue: btrfs-worker btrfs_work_helper RIP: 0010:blkcg_punt_bio_submit+0x47/0x130 block/blk-cgroup.c:243 Code: ae 13 fd 4c 8d 73 50 4c 89 f0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 f7 e8 07 06 7f fd 4d 8b 36 4d 8d 7e 30 4c 89 f8 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 ff e8 eb 05 7f fd 49 83 3f 00 0f 84 ab 00 RSP: 0000:ffffc90000a17a28 EFLAGS: 00010206 RAX: 0000000000000006 RBX: ffff888117071348 RCX: ffff8881032f5940 RDX: 0000000000000000 RSI: 0000000004000000 RDI: ffff888117071348 RBP: dffffc0000000000 R08: ffff8881bb74406f R09: 1ffff110376e880d R10: dffffc0000000000 R11: ffffed10376e880e R12: ffff88816c5e6f08 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000030 FS: 0000000000000000(0000) GS:ffff88818d9cb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f05d5660000 CR3: 0000000172eb2000 CR4: 00000000000006f0 Call Trace: run_ordered_work fs/btrfs/async-thread.c:243 [inline] btrfs_work_helper+0x577/0xc50 fs/btrfs/async-thread.c:322 process_one_work kernel/workqueue.c:3314 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3397 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3478 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:blkcg_punt_bio_submit+0x47/0x130 block/blk-cgroup.c:243 Code: ae 13 fd 4c 8d 73 50 4c 89 f0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 f7 e8 07 06 7f fd 4d 8b 36 4d 8d 7e 30 4c 89 f8 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 ff e8 eb 05 7f fd 49 83 3f 00 0f 84 ab 00 RSP: 0000:ffffc90000a17a28 EFLAGS: 00010206 RAX: 0000000000000006 RBX: ffff888117071348 RCX: ffff8881032f5940 RDX: 0000000000000000 RSI: 0000000004000000 RDI: ffff888117071348 RBP: dffffc0000000000 R08: ffff8881bb74406f R09: 1ffff110376e880d R10: dffffc0000000000 R11: ffffed10376e880e R12: ffff88816c5e6f08 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000030 FS: 0000000000000000(0000) GS:ffff8882a8fcb000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efceadf26a8 CR3: 0000000115190000 CR4: 00000000000006f0 ---------------- Code disassembly (best guess): 0: ae scas %es:(%rdi),%al 1: 13 fd adc %ebp,%edi 3: 4c 8d 73 50 lea 0x50(%rbx),%r14 7: 4c 89 f0 mov %r14,%rax a: 48 c1 e8 03 shr $0x3,%rax e: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) 12: 74 08 je 0x1c 14: 4c 89 f7 mov %r14,%rdi 17: e8 07 06 7f fd call 0xfd7f0623 1c: 4d 8b 36 mov (%r14),%r14 1f: 4d 8d 7e 30 lea 0x30(%r14),%r15 23: 4c 89 f8 mov %r15,%rax 26: 48 c1 e8 03 shr $0x3,%rax * 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 4c 89 ff mov %r15,%rdi 33: e8 eb 05 7f fd call 0xfd7f0623 38: 49 83 3f 00 cmpq $0x0,(%r15) 3c: 0f .byte 0xf 3d: 84 .byte 0x84 3e: ab stos %eax,%es:(%rdi) *** 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. To test a patch for this bug, please reply with `#syz test` (should be on a separate line). The patch should be attached to the email. Note: arguments like custom git repos and branches are not supported.