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AJvYcCWBV49RYXWq73/MWra2LUZejXB35UYuhef4Vu6cMx4thG5IUDSZT8JJcwD0B1BhJ11JVTzRBv36D8H3i7Oe@vger.kernel.org X-Gm-Message-State: AOJu0YwIQkmbk+ceWzxu8HAy8dxHCNMm5fxB0uKmObMkep3X2Zp6buE4 /lxmXDZUq5aqyftZE3yoHsktf4DOxyf5CV+xtKDGl7PIysOz1CsmrUPibYpphSv+I2oyz8HqNT3 BnysmC1yuaBxqg9OT2mBez7T4SJ0qaP0F2lN1PvakVKphMlMXNDn1u1/MEbQ= Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:498e:b0:65b:2935:f935 with SMTP id 006d021491bc7-661179c2396mr1433844eaf.44.1768580017428; Fri, 16 Jan 2026 08:13:37 -0800 (PST) Date: Fri, 16 Jan 2026 08:13:37 -0800 In-Reply-To: <20260116100818.7576-1-kundan.kumar@samsung.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <696a63b1.050a0220.58bed.006b.GAE@google.com> Subject: [syzbot ci] Re: AG aware parallel writeback for XFS From: syzbot ci To: amir73il@gmail.com, anuj20.g@samsung.com, axboe@kernel.dk, brauner@kernel.org, cem@kernel.org, clm@meta.com, dave@stgolabs.net, david@fromorbit.com, djwong@kernel.org, gost.dev@samsung.com, hch@lst.de, jack@suse.cz, joshi.k@samsung.com, kundan.kumar@samsung.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-xfs@vger.kernel.org, mcgrof@kernel.org, ritesh.list@gmail.com, viro@zeniv.linux.org.uk, vishak.g@samsung.com, wangyufei@vivo.com, willy@infradead.org Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot ci has tested the following series [v3] AG aware parallel writeback for XFS https://lore.kernel.org/all/20260116100818.7576-1-kundan.kumar@samsung.com * [PATCH v3 1/6] iomap: add write ops hook to attach metadata to folios * [PATCH v3 2/6] xfs: add helpers to pack AG prediction info for per-folio tracking * [PATCH v3 3/6] xfs: add per-inode AG prediction map and dirty-AG bitmap * [PATCH v3 4/6] xfs: tag folios with AG number during buffered write via iomap attach hook * [PATCH v3 5/6] xfs: add per-AG writeback workqueue infrastructure * [PATCH v3 6/6] xfs: offload writeback by AG using per-inode dirty bitmap and per-AG workers and found the following issue: WARNING in xfs_init_ag_writeback Full report is available here: https://ci.syzbot.org/series/0e34236b-3594-400f-b9cd-6f59b196014f *** WARNING in xfs_init_ag_writeback tree: mm-new URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/akpm/mm.git base: eeb33083cc4749bdb61582eaeb5c200702607703 arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/f21aae46-4d21-4410-9132-190ad8ae3994/config C repro: https://ci.syzbot.org/findings/24ec6312-5e15-4750-aa2a-08d381daca26/c_repro syz repro: https://ci.syzbot.org/findings/24ec6312-5e15-4750-aa2a-08d381daca26/syz_repro loop2: detected capacity change from 0 to 32768 ------------[ cut here ]------------ kmem_cache of name 'xfs_ag_wb_task' already exists WARNING: mm/slab_common.c:110 at kmem_cache_sanity_check mm/slab_common.c:109 [inline], CPU#1: syz.2.19/6098 WARNING: mm/slab_common.c:110 at __kmem_cache_create_args+0x99/0x310 mm/slab_common.c:310, CPU#1: syz.2.19/6098 Modules linked in: CPU: 1 UID: 0 PID: 6098 Comm: syz.2.19 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:kmem_cache_sanity_check mm/slab_common.c:109 [inline] RIP: 0010:__kmem_cache_create_args+0x9c/0x310 mm/slab_common.c:310 Code: 43 8e 4d 8b 24 24 49 81 fc b8 78 43 8e 74 20 49 8b 7c 24 f8 48 89 de e8 f2 c0 67 09 85 c0 75 e2 48 8d 3d f7 ca bc 0d 48 89 de <67> 48 0f b9 3a 48 89 df be 20 00 00 00 e8 92 c2 67 09 48 85 c0 0f RSP: 0018:ffffc90003817a08 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffff8bc734a0 RCX: 0000000000000007 RDX: 000000008bc73406 RSI: ffffffff8bc734a0 RDI: ffffffff8fc6ee40 RBP: 0000000000080000 R08: ffffffff8fc26e77 R09: 1ffffffff1f84dce R10: dffffc0000000000 R11: fffffbfff1f84dcf R12: ffff88810b7a7300 R13: ffff888115440000 R14: ffffc90003817aa0 R15: 0000000000000190 FS: 0000555567cf7500(0000) GS:ffff8882a9a05000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f049ffff000 CR3: 00000001b9726000 CR4: 00000000000006f0 Call Trace: __kmem_cache_create include/linux/slab.h:384 [inline] xfs_init_ag_writeback+0x41b/0x570 fs/xfs/xfs_aops.c:890 xfs_fs_fill_super+0x7e3/0x1640 fs/xfs/xfs_super.c:1759 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1691 vfs_get_tree+0x92/0x2a0 fs/super.c:1751 fc_mount fs/namespace.c:1199 [inline] do_new_mount_fc fs/namespace.c:3636 [inline] do_new_mount+0x329/0xa50 fs/namespace.c:3712 do_mount fs/namespace.c:4035 [inline] __do_sys_mount fs/namespace.c:4224 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4201 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f32c139bf4a Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd30494b68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007ffd30494bf0 RCX: 00007f32c139bf4a RDX: 0000200000009740 RSI: 0000200000009780 RDI: 00007ffd30494bb0 RBP: 0000200000009740 R08: 00007ffd30494bf0 R09: 0000000000004010 R10: 0000000000004010 R11: 0000000000000246 R12: 0000200000009780 R13: 00007ffd30494bb0 R14: 0000000000009768 R15: 0000200000000300 ---------------- Code disassembly (best guess): 0: 43 8e 4d 8b rex.XB mov -0x75(%r13),%cs 4: 24 24 and $0x24,%al 6: 49 81 fc b8 78 43 8e cmp $0xffffffff8e4378b8,%r12 d: 74 20 je 0x2f f: 49 8b 7c 24 f8 mov -0x8(%r12),%rdi 14: 48 89 de mov %rbx,%rsi 17: e8 f2 c0 67 09 call 0x967c10e 1c: 85 c0 test %eax,%eax 1e: 75 e2 jne 0x2 20: 48 8d 3d f7 ca bc 0d lea 0xdbccaf7(%rip),%rdi # 0xdbccb1e 27: 48 89 de mov %rbx,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 48 89 df mov %rbx,%rdi 32: be 20 00 00 00 mov $0x20,%esi 37: e8 92 c2 67 09 call 0x967c2ce 3c: 48 85 c0 test %rax,%rax 3f: 0f .byte 0xf *** 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.