================================================================== BUG: KCSAN: data-race in data_alloc / data_push_tail write to 0xffffffff84500420 of 8 bytes by task 17721 on cpu 1: data_alloc+0x205/0x2b0 kernel/printk/printk_ringbuffer.c:1071 prb_reserve+0x8f0/0xbc0 kernel/printk/printk_ringbuffer.c:1549 vprintk_store+0x3e9/0x9c0 kernel/printk/printk.c:2029 vprintk_emit+0xca/0x3d0 kernel/printk/printk.c:2081 vprintk_default+0x22/0x30 kernel/printk/printk.c:2115 vprintk_func+0x137/0x140 kernel/printk/printk_safe.c:401 printk+0x62/0x82 kernel/printk/printk.c:2146 blk_add_partition block/partitions/core.c:570 [inline] blk_add_partitions+0x63f/0xa80 block/partitions/core.c:661 bdev_disk_changed+0x1a7/0x200 fs/block_dev.c:1272 loop_reread_partitions drivers/block/loop.c:655 [inline] loop_set_status+0x75f/0x7e0 drivers/block/loop.c:1418 lo_ioctl+0x758/0x11f0 drivers/block/loop.c:1486 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:583 block_ioctl+0x6d/0x80 fs/block_dev.c:1671 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffffffff84500420 of 8 bytes by task 17747 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_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:2007 vprintk_emit+0xca/0x3d0 kernel/printk/printk.c:2081 vprintk_default+0x22/0x30 kernel/printk/printk.c:2115 vprintk_func+0x137/0x140 kernel/printk/printk_safe.c:401 printk+0x62/0x82 kernel/printk/printk.c:2146 disk_unlock_native_capacity block/partitions/core.c:531 [inline] blk_add_partition block/partitions/core.c:573 [inline] blk_add_partitions+0x712/0xa80 block/partitions/core.c:661 bdev_disk_changed+0x1a7/0x200 fs/block_dev.c:1272 loop_reread_partitions drivers/block/loop.c:655 [inline] loop_set_status+0x75f/0x7e0 drivers/block/loop.c:1418 lo_ioctl+0x758/0x11f0 drivers/block/loop.c:1486 blkdev_ioctl+0x1d0/0x3c0 block/ioctl.c:583 block_ioctl+0x6d/0x80 fs/block_dev.c:1671 vfs_ioctl fs/ioctl.c:48 [inline] __do_sys_ioctl fs/ioctl.c:753 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739 do_syscall_64+0x34/0x50 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 17747 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================