syz.3.1642[8369] is installing a program with bpf_probe_write_user helper that may corrupt user memory! syz.3.1642[8369] is installing a program with bpf_probe_write_user helper that may corrupt user memory! syz.3.1642[8369] is installing a program with bpf_probe_write_user helper that may corrupt user memory! ================================================================== BUG: KCSAN: data-race in data_push_tail / number write to 0xffffffff88b9d397 of 1 bytes by task 8372 on cpu 0: number+0x7d0/0xa90 lib/vsprintf.c:564 vsnprintf+0xa44/0xe30 lib/vsprintf.c:2869 vscnprintf+0x42/0x90 lib/vsprintf.c:2909 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2197 vprintk_store+0x570/0x810 kernel/printk/printk.c:2311 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68 _printk+0x7a/0xa0 kernel/printk/printk.c:2432 set_capacity_and_notify+0xff/0x160 block/genhd.c:86 loop_set_size+0x2e/0x70 drivers/block/loop.c:232 loop_configure+0x8a7/0xa30 drivers/block/loop.c:1102 lo_ioctl+0x5f6/0x11c0 blkdev_ioctl+0x359/0x450 block/ioctl.c:693 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xcd/0x140 fs/ioctl.c:893 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893 x64_sys_call+0x15cc/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff88b9d390 of 8 bytes by task 8369 on cpu 1: data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline] data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2301 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68 _printk+0x7a/0xa0 kernel/printk/printk.c:2432 bpf_get_probe_write_proto+0x8b/0x90 kernel/trace/bpf_trace.c:365 bpf_tracing_func_proto+0x596/0x790 kernel/trace/bpf_trace.c:1466 raw_tp_prog_func_proto+0x65/0xc0 kernel/trace/bpf_trace.c:1938 do_misc_fixups kernel/bpf/verifier.c:21213 [inline] bpf_check+0x75a2/0xcd90 kernel/bpf/verifier.c:22443 bpf_prog_load+0xed4/0x1070 kernel/bpf/syscall.c:2915 __sys_bpf+0x463/0x7a0 kernel/bpf/syscall.c:5717 __do_sys_bpf kernel/bpf/syscall.c:5824 [inline] __se_sys_bpf kernel/bpf/syscall.c:5822 [inline] __x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5822 x64_sys_call+0x2625/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:322 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000000ffffe6e6 -> 0x00206d6f72662065 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 8369 Comm: syz.3.1642 Not tainted 6.11.0-syzkaller-08833-gde5cb0dcb74c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 ==================================================================