CPU: 1 UID: 0 PID: 29855 Comm: syz.6.4101 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 lib/dump_stack.c:120 ================================================================== BUG: KCSAN: data-race in data_push_tail / vsnprintf write to 0xffffffff88e3fe77 of 32 bytes by task 29849 on cpu 0: vsnprintf+0x2ce/0x890 lib/vsprintf.c:2826 vscnprintf+0x41/0x90 lib/vsprintf.c:2939 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 set_capacity_and_notify+0x14c/0x1f0 block/genhd.c:93 loop_set_size+0x2e/0x70 drivers/block/loop.c:210 loop_configure+0x8d3/0xa50 drivers/block/loop.c:1068 lo_ioctl+0x559/0x15d0 drivers/block/loop.c:-1 blkdev_ioctl+0x34f/0x440 block/ioctl.c:704 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:893 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893 x64_sys_call+0x19a8/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffffffff88e3fe80 of 8 bytes by task 29855 on cpu 1: data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline] data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82 _printk+0x79/0xa0 kernel/printk/printk.c:2475 printk_stack_address arch/x86/kernel/dumpstack.c:70 [inline] show_trace_log_lvl+0x4e3/0x560 arch/x86/kernel/dumpstack.c:282 __dump_stack+0x1d/0x30 lib/dump_stack.c:94 dump_stack_lvl+0xe8/0x140 lib/dump_stack.c:120 dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x265/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37 __copy_to_user_inatomic include/linux/uaccess.h:132 [inline] copy_to_user_nofault+0x7f/0x120 mm/maccess.c:156 ____bpf_probe_write_user kernel/trace/bpf_trace.c:348 [inline] bpf_probe_write_user+0x83/0xc0 kernel/trace/bpf_trace.c:326 bpf_prog_6303d92f98284ad8+0x44/0x4c bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] bpf_trace_run2+0x104/0x1c0 kernel/trace/bpf_trace.c:2299 __traceiter_kfree+0x2e/0x50 include/trace/events/kmem.h:94 __do_trace_kfree include/trace/events/kmem.h:94 [inline] trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x27b/0x320 mm/slub.c:4829 ethnl_update_bitset32_verbose net/ethtool/bitset.c:516 [inline] ethnl_update_bitset32+0xdae/0xde0 net/ethtool/bitset.c:609 ethnl_update_bitset+0x3a/0x50 net/ethtool/bitset.c:869 ethnl_update_linkmodes net/ethtool/linkmodes.c:281 [inline] ethnl_set_linkmodes+0x373/0x820 net/ethtool/linkmodes.c:333 ethnl_default_set_doit+0x316/0x5b0 net/ethtool/netlink.c:905 genl_family_rcv_msg_doit+0x140/0x1b0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x422/0x460 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5a5/0x680 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:727 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0x00000001000007db -> 0x7974696361706163 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 29855 Comm: syz.6.4101 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(voluntary) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 ================================================================== dump_stack+0x15/0x1b lib/dump_stack.c:129 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x265/0x280 lib/fault-inject.c:174 should_fail+0xb/0x20 lib/fault-inject.c:184 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37 __copy_to_user_inatomic include/linux/uaccess.h:132 [inline] copy_to_user_nofault+0x7f/0x120 mm/maccess.c:156 ____bpf_probe_write_user kernel/trace/bpf_trace.c:348 [inline] bpf_probe_write_user+0x83/0xc0 kernel/trace/bpf_trace.c:326 bpf_prog_6303d92f98284ad8+0x44/0x4c bpf_dispatcher_nop_func include/linux/bpf.h:1322 [inline] __bpf_prog_run include/linux/filter.h:718 [inline] bpf_prog_run include/linux/filter.h:725 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2258 [inline] bpf_trace_run2+0x104/0x1c0 kernel/trace/bpf_trace.c:2299 __traceiter_kfree+0x2e/0x50 include/trace/events/kmem.h:94 __do_trace_kfree include/trace/events/kmem.h:94 [inline] trace_kfree include/trace/events/kmem.h:94 [inline] kfree+0x27b/0x320 mm/slub.c:4829 ethnl_update_bitset32_verbose net/ethtool/bitset.c:516 [inline] ethnl_update_bitset32+0xdae/0xde0 net/ethtool/bitset.c:609 ethnl_update_bitset+0x3a/0x50 net/ethtool/bitset.c:869 ethnl_update_linkmodes net/ethtool/linkmodes.c:281 [inline] ethnl_set_linkmodes+0x373/0x820 net/ethtool/linkmodes.c:333 ethnl_default_set_doit+0x316/0x5b0 net/ethtool/netlink.c:905 genl_family_rcv_msg_doit+0x140/0x1b0 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x422/0x460 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2552 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline] netlink_unicast+0x5a5/0x680 net/netlink/af_netlink.c:1346 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896 sock_sendmsg_nosec net/socket.c:712 [inline] __sock_sendmsg+0x145/0x180 net/socket.c:727 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620 __sys_sendmsg net/socket.c:2652 [inline] __do_sys_sendmsg net/socket.c:2657 [inline] __se_sys_sendmsg net/socket.c:2655 [inline] __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff4a00de929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ff49e747038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ff4a0305fa0 RCX: 00007ff4a00de929 RDX: 0000000020008000 RSI: 0000200000000480 RDI: 0000000000000003 RBP: 00007ff49e747090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 00007ff4a0305fa0 R15: 00007ffeecc7f2d8