================================================================== BUG: KCSAN: data-race in data_push_tail / string write to 0xffffffff8413ceba of 1 bytes by task 20438 on cpu 0: string_nocheck lib/vsprintf.c:642 [inline] string+0xa1/0x210 lib/vsprintf.c:720 vsnprintf+0xab0/0xed0 lib/vsprintf.c:2797 vscnprintf+0x29/0x80 lib/vsprintf.c:2900 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_partitions block/partitions/core.c:644 [inline] bdev_disk_changed+0xce1/0xea0 block/partitions/core.c:697 loop_reread_partitions drivers/block/loop.c:652 [inline] loop_set_status+0x4dc/0x5a0 drivers/block/loop.c:1510 lo_ioctl+0x764/0x1210 drivers/block/loop.c:1620 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 0xffffffff8413ceb8 of 8 bytes by task 20408 on cpu 1: data_make_reusable kernel/printk/printk_ringbuffer.c:587 [inline] data_push_tail+0x125/0x460 kernel/printk/printk_ringbuffer.c:672 data_realloc kernel/printk/printk_ringbuffer.c:1132 [inline] prb_reserve_in_last+0x71c/0xba0 kernel/printk/printk_ringbuffer.c:1421 vprintk_store+0x311/0x9c0 kernel/printk/printk.c:2083 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 disk_unlock_native_capacity block/partitions/core.c:537 [inline] blk_add_partitions block/partitions/core.c:647 [inline] bdev_disk_changed+0xd98/0xea0 block/partitions/core.c:697 loop_reread_partitions drivers/block/loop.c:652 [inline] loop_set_status+0x4dc/0x5a0 drivers/block/loop.c:1510 lo_ioctl+0x764/0x1210 drivers/block/loop.c:1620 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 value changed: 0x0000000100029747 -> 0x70203a32706f6f6c Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 20408 Comm: syz-executor.5 Not tainted 5.14.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================