loop5: detected capacity change from 0 to 264192 ================================================================== BUG: KCSAN: data-race in data_alloc / data_push_tail write to 0xffffffff870a1748 of 8 bytes by task 20601 on cpu 1: data_alloc+0x205/0x2b0 kernel/printk/printk_ringbuffer.c:1074 prb_reserve+0x897/0xbd0 kernel/printk/printk_ringbuffer.c:1555 vprintk_store+0x51c/0xb50 kernel/printk/printk.c:2196 vprintk_emit+0xcc/0x430 kernel/printk/printk.c:2252 vprintk_default+0x22/0x30 kernel/printk/printk.c:2282 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50 _printk+0x76/0x96 kernel/printk/printk.c:2292 set_capacity_and_notify+0x176/0x1d0 block/genhd.c:90 loop_set_size+0x2e/0x70 drivers/block/loop.c:237 loop_configure+0xb1b/0xc30 drivers/block/loop.c:1100 lo_ioctl+0x641/0x1290 blkdev_ioctl+0x20e/0x440 block/ioctl.c:614 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd read to 0xffffffff870a1748 of 8 bytes by task 20603 on cpu 0: data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline] data_push_tail+0x10f/0x440 kernel/printk/printk_ringbuffer.c:675 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1046 prb_reserve+0x897/0xbd0 kernel/printk/printk_ringbuffer.c:1555 vprintk_store+0x51c/0xb50 kernel/printk/printk.c:2196 vprintk_emit+0xcc/0x430 kernel/printk/printk.c:2252 vprintk_default+0x22/0x30 kernel/printk/printk.c:2282 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50 _printk+0x76/0x96 kernel/printk/printk.c:2292 set_capacity_and_notify+0x176/0x1d0 block/genhd.c:90 loop_set_size+0x2e/0x70 drivers/block/loop.c:237 loop_configure+0xb1b/0xc30 drivers/block/loop.c:1100 lo_ioctl+0x641/0x1290 blkdev_ioctl+0x20e/0x440 block/ioctl.c:614 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:856 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd value changed: 0x00000001000000b0 -> 0x0000000100000c65 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 20603 Comm: syz-executor.5 Not tainted 6.0.0-rc4-syzkaller-00284-gce888220d5c7-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 ================================================================== EXT4-fs (loop5): ext4_check_descriptors: Checksum for group 0 failed (60729!=0) EXT4-fs (loop5): group descriptors corrupted!