================================================================== BUG: KCSAN: data-race in data_push_tail / number write to 0xffffffff8455b6fa of 1 bytes by task 27742 on cpu 1: number+0x836/0xb50 lib/vsprintf.c:555 vsnprintf+0xb6d/0xed0 lib/vsprintf.c:2856 vscnprintf+0x29/0x80 lib/vsprintf.c:2893 printk_sprint kernel/printk/printk.c:2012 [inline] vprintk_store+0x4c1/0x9c0 kernel/printk/printk.c:2115 vprintk_emit+0xca/0x3d0 kernel/printk/printk.c:2157 vprintk_default+0x22/0x30 kernel/printk/printk.c:2185 vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392 printk+0x62/0x87 kernel/printk/printk.c:2216 blk_add_partition block/partitions/core.c:568 [inline] blk_add_partitions block/partitions/core.c:650 [inline] bdev_disk_changed+0xa00/0xed0 block/partitions/core.c:692 loop_reread_partitions drivers/block/loop.c:652 [inline] loop_set_status+0x4dc/0x5a0 drivers/block/loop.c:1512 lo_ioctl+0x764/0x1210 drivers/block/loop.c:1622 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:585 block_ioctl+0x6d/0x80 fs/block_dev.c:1602 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:1069 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:1055 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:1055 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffffff8455b6f8 of 8 bytes by task 27764 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:587 [inline] data_push_tail+0x125/0x460 kernel/printk/printk_ringbuffer.c:672 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1043 prb_reserve+0x8f0/0xbc0 kernel/printk/printk_ringbuffer.c:1549 vprintk_store+0x3e9/0x9c0 kernel/printk/printk.c:2105 vprintk_emit+0xca/0x3d0 kernel/printk/printk.c:2157 vprintk_default+0x22/0x30 kernel/printk/printk.c:2185 vprintk+0x15a/0x170 kernel/printk/printk_safe.c:392 printk+0x62/0x87 kernel/printk/printk.c:2216 __ext4_msg+0x103/0x110 fs/ext4/super.c:909 ext4_feature_set_ok+0x7f/0x1f0 fs/ext4/super.c:3311 ext4_fill_super+0x1908/0x8080 fs/ext4/super.c:4421 mount_bdev+0x1e8/0x290 fs/super.c:1368 ext4_mount+0x2d/0x40 fs/ext4/super.c:6634 legacy_get_tree+0x70/0xc0 fs/fs_context.c:592 vfs_get_tree+0x4a/0x1a0 fs/super.c:1498 do_new_mount fs/namespace.c:2905 [inline] path_mount+0x11d4/0x1ce0 fs/namespace.c:3235 do_mount fs/namespace.c:3248 [inline] __do_sys_mount fs/namespace.c:3456 [inline] __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3433 __x64_sys_mount+0x63/0x70 fs/namespace.c:3433 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x0000000100000fec -> 0x0000000100327020 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 27764 Comm: syz-executor.2 Not tainted 5.13.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ================================================================== sd 0:0:1:0: [sg0] tag#5690 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s sd 0:0:1:0: [sg0] tag#5690 CDB: Search High sd 0:0:1:0: [sg0] tag#5690 CDB[00]: 30 c6 6b 87 7f d3 b0 cb 86 4d 2e 4e 2d aa 3e aa sd 0:0:1:0: [sg0] tag#5690 CDB[10]: 4a fd ae f3 a6 e3 af 04 09 19 44 6f 91 19 f8 ab sd 0:0:1:0: [sg0] tag#5690 CDB[20]: 86 55 b2 18 7c 2b fe de 71 80 2c 18 b6 3b 09 34 sd 0:0:1:0: [sg0] tag#5690 CDB[30]: d1 b6 4a bb 73 a8 d3 8d 5c 6a d8 ea 99 2b af 3b sd 0:0:1:0: [sg0] tag#5690 CDB[40]: a1 a0 f2 b3 31 ee 2a f6 e1 bf f6 d0 5a 1a ee d4 sd 0:0:1:0: [sg0] tag#5690 CDB[50]: 7b 85 8e 9f 1d 0d 04 84 75 33 d5 73 ae 43 20 21 sd 0:0:1:0: [sg0] tag#5690 CDB[60]: a1 96 b4 e0 8d 76 d4 9a f5 f7 bf 3d 26 21 21 b8 sd 0:0:1:0: [sg0] tag#5690 CDB[70]: 4d c8 94 b2 e9 a2 ad a8 a2 6a 6e 27 72 3f 6c d5 sd 0:0:1:0: [sg0] tag#5690 CDB[80]: f5 9e f8 d8 1c ec 52 09 b6 ab c9 cc f9 bf 6b 5f sd 0:0:1:0: [sg0] tag#5690 CDB[90]: 4a 5e f0 9a 9c 70 4d 46 4c 84 17 25 a5 dd 65 d9 sd 0:0:1:0: [sg0] tag#5690 CDB[a0]: 84 a3 e5 88 a6 7f 1f 62 7e 93 20 0f 7b 0c 73 81 sd 0:0:1:0: [sg0] tag#5690 CDB[b0]: e4 c5 d5 b1 a7 79 48 7b 82 42 24 ee 00 18 46 a0 sd 0:0:1:0: [sg0] tag#5690 CDB[c0]: 9f 29 3c 40 93 34 d7 c2 c0 e6 c8 2d 83 f1 c3 87 sd 0:0:1:0: [sg0] tag#5690 CDB[d0]: f9 43 23 0d bf 33 57 2f 21 97 1c 96 ed 27 06 26 sd 0:0:1:0: [sg0] tag#5690 CDB[e0]: fd 15 fc 6b 9e fb bd 2a fa 5c 99 5c 45 4d bc aa sd 0:0:1:0: [sg0] tag#5690 CDB[f0]: c7 de 07 99 52 55 sd 0:0:1:0: [sg0] tag#5674 FAILED Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK cmd_age=0s sd 0:0:1:0: [sg0] tag#5674 CDB: Search High sd 0:0:1:0: [sg0] tag#5674 CDB[00]: 30 c6 6b 87 7f d3 b0 cb 86 4d 2e 4e 2d aa 3e aa sd 0:0:1:0: [sg0] tag#5674 CDB[10]: 4a fd ae f3 a6 e3 af 04 09 19 44 6f 91 19 f8 ab sd 0:0:1:0: [sg0] tag#5674 CDB[20]: 86 55 b2 18 7c 2b fe de 71 80 2c 18 b6 3b 09 34 sd 0:0:1:0: [sg0] tag#5674 CDB[30]: d1 b6 4a bb 73 a8 d3 8d 5c 6a d8 ea 99 2b af 3b sd 0:0:1:0: [sg0] tag#5674 CDB[40]: a1 a0 f2 b3 31 ee 2a f6 e1 bf f6 d0 5a 1a ee d4 sd 0:0:1:0: [sg0] tag#5674 CDB[50]: 7b 85 8e 9f 1d 0d 04 84 75 33 d5 73 ae 43 20 21 sd 0:0:1:0: [sg0] tag#5674 CDB[60]: a1 96 b4 e0 8d 76 d4 9a f5 f7 bf 3d 26 21 21 b8 sd 0:0:1:0: [sg0] tag#5674 CDB[70]: 4d c8 94 b2 e9 a2 ad a8 a2 6a 6e 27 72 3f 6c d5 sd 0:0:1:0: [sg0] tag#5674 CDB[80]: f5 9e f8 d8 1c ec 52 09 b6 ab c9 cc f9 bf 6b 5f sd 0:0:1:0: [sg0] tag#5674 CDB[90]: 4a 5e f0 9a 9c 70 4d 46 4c 84 17 25 a5 dd 65 d9 sd 0:0:1:0: [sg0] tag#5674 CDB[a0]: 84 a3 e5 88 a6 7f 1f 62 7e 93 20 0f 7b 0c 73 81 sd 0:0:1:0: [sg0] tag#5674 CDB[b0]: e4 c5 d5 b1 a7 79 48 7b 82 42 24 ee 00 18 46 a0 sd 0:0:1:0: [sg0] tag#5674 CDB[c0]: 9f 29 3c 40 93 34 d7 c2 c0 e6 c8 2d 83 f1 c3 87 sd 0:0:1:0: [sg0] tag#5674 CDB[d0]: f9 43 23 0d bf 33 57 2f 21 97 1c 96 ed 27 06 26 sd 0:0:1:0: [sg0] tag#5674 CDB[e0]: fd 15 fc 6b 9e fb bd 2a fa 5c 99 5c 45 4d bc aa sd 0:0:1:0: [sg0] tag#5674 CDB[f0]: c7 de 07 99 52 55