================================================================== BUG: KCSAN: data-race in data_alloc / prb_reserve write to 0xffffffff85c7c020 of 8 bytes by task 9879 on cpu 1: data_alloc+0x291/0x2c0 kernel/printk/printk_ringbuffer.c:1088 prb_reserve+0x897/0xbc0 kernel/printk/printk_ringbuffer.c:1555 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45 _printk+0x7a/0xa0 kernel/printk/printk.c:2328 printk_stack_address arch/x86/kernel/dumpstack.c:72 [inline] show_trace_log_lvl+0x42e/0x510 arch/x86/kernel/dumpstack.c:285 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xda/0x130 lib/dump_stack.c:106 dump_stack+0x15/0x20 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:52 [inline] should_fail_ex+0x21f/0x230 lib/fault-inject.c:153 __should_failslab+0x92/0xa0 mm/failslab.c:44 should_failslab+0x9/0x20 mm/slub.c:3747 slab_pre_alloc_hook mm/slub.c:3763 [inline] slab_alloc_node mm/slub.c:3842 [inline] kmem_cache_alloc+0x56/0x2d0 mm/slub.c:3867 skb_clone+0x154/0x1e0 net/core/skbuff.c:1954 __netlink_deliver_tap_skb net/netlink/af_netlink.c:300 [inline] __netlink_deliver_tap+0x2bd/0x4c0 net/netlink/af_netlink.c:325 netlink_deliver_tap net/netlink/af_netlink.c:338 [inline] netlink_deliver_tap_kernel net/netlink/af_netlink.c:347 [inline] netlink_unicast_kernel net/netlink/af_netlink.c:1340 [inline] netlink_unicast+0x631/0x660 net/netlink/af_netlink.c:1367 netlink_sendmsg+0x66e/0x770 net/netlink/af_netlink.c:1908 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg net/socket.c:745 [inline] ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2584 ___sys_sendmsg net/socket.c:2638 [inline] __sys_sendmsg+0x1e9/0x270 net/socket.c:2667 __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x46/0x50 net/socket.c:2674 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b read to 0xffffffff85c7c020 of 8 bytes by task 9890 on cpu 0: desc_read kernel/printk/printk_ringbuffer.c:478 [inline] desc_push_tail kernel/printk/printk_ringbuffer.c:774 [inline] desc_reserve kernel/printk/printk_ringbuffer.c:920 [inline] prb_reserve+0x229/0xbc0 kernel/printk/printk_ringbuffer.c:1505 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45 _printk+0x7a/0xa0 kernel/printk/printk.c:2328 fail_dump lib/fault-inject.c:45 [inline] should_fail_ex+0x207/0x230 lib/fault-inject.c:153 should_fail+0xb/0x10 lib/fault-inject.c:163 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37 _copy_to_user+0x1e/0x90 lib/usercopy.c:37 copy_to_user include/linux/uaccess.h:191 [inline] simple_read_from_buffer+0xa0/0x110 fs/libfs.c:1034 proc_fail_nth_read+0xfc/0x140 fs/proc/base.c:1424 vfs_read+0x19e/0x6a0 fs/read_write.c:474 ksys_read+0xeb/0x1a0 fs/read_write.c:619 __do_sys_read fs/read_write.c:629 [inline] __se_sys_read fs/read_write.c:627 [inline] __x64_sys_read+0x42/0x50 fs/read_write.c:627 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b value changed: 0x00000000000933d8 -> 0x0000000000111138 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 9890 Comm: syz-executor.0 Not tainted 6.8.0-rc6-syzkaller-00250-g04b8076df253 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 ================================================================== FAULT_INJECTION: forcing a failure. name fail_usercopy, interval 1, probability 0, space 0, times 0 CPU: 0 PID: 9890 Comm: syz-executor.0 Not tainted 6.8.0-rc6-syzkaller-00250-g04b8076df253 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xda/0x130 lib/dump_stack.c:106 dump_stack+0x15/0x20 lib/dump_stack.c:113 fail_dump lib/fault-inject.c:52 [inline] should_fail_ex+0x21f/0x230 lib/fault-inject.c:153 should_fail+0xb/0x10 lib/fault-inject.c:163 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37 _copy_to_user+0x1e/0x90 lib/usercopy.c:37 copy_to_user include/linux/uaccess.h:191 [inline] simple_read_from_buffer+0xa0/0x110 fs/libfs.c:1034 proc_fail_nth_read+0xfc/0x140 fs/proc/base.c:1424 vfs_read+0x19e/0x6a0 fs/read_write.c:474 ksys_read+0xeb/0x1a0 fs/read_write.c:619 __do_sys_read fs/read_write.c:629 [inline] __se_sys_read fs/read_write.c:627 [inline] __x64_sys_read+0x42/0x50 fs/read_write.c:627 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7fc3f5d36a4c Code: ec 28 48 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 59 81 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 34 44 89 c7 48 89 44 24 08 e8 af 81 02 00 48 RSP: 002b:00007fc3f50b90c0 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fc3f5e65f80 RCX: 00007fc3f5d36a4c RDX: 000000000000000f RSI: 00007fc3f50b9130 RDI: 0000000000000004 RBP: 00007fc3f50b9120 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 R13: 000000000000000b R14: 00007fc3f5e65f80 R15: 00007ffe5f490fa8