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BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
CPU: 0 PID: 8690 Comm: syz-executor155 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423
 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253
 instrument_copy_to_user include/linux/instrumented.h:91 [inline]
 copyout lib/iov_iter.c:147 [inline]
 _copy_to_iter+0x626/0x2de0 lib/iov_iter.c:640
 copy_to_iter include/linux/uio.h:138 [inline]
 memcpy_to_msg include/linux/skbuff.h:3571 [inline]
 bcm_recvmsg+0x2ca/0x8e0 net/can/bcm.c:1612
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 __sys_recvfrom+0x69a/0xa10 net/socket.c:2052
 __compat_sys_recvfrom net/compat.c:509 [inline]
 __do_compat_sys_recvfrom net/compat.c:522 [inline]
 __se_compat_sys_recvfrom+0x122/0x150 net/compat.c:518
 __ia32_compat_sys_recvfrom+0x6e/0x90 net/compat.c:518
 do_syscall_32_irqs_on arch/x86/entry/common.c:430 [inline]
 __do_fast_syscall_32+0x2af/0x480 arch/x86/entry/common.c:477
 do_fast_syscall_32+0x6b/0xd0 arch/x86/entry/common.c:505
 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:554
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f7d549
Code: Bad RIP value.
RSP: 002b:00000000f7f781dc EFLAGS: 00000292 ORIG_RAX: 0000000000000173
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000040
RDX: 0000000000000032 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310
 kmsan_memcpy_memmove_metadata+0x272/0x2e0 mm/kmsan/kmsan.c:247
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:267
 __msan_memcpy+0x43/0x50 mm/kmsan/kmsan_instr.c:116
 skb_put_data include/linux/skbuff.h:2260 [inline]
 bcm_send_to_user+0x260/0x890 net/can/bcm.c:327
 bcm_tx_timeout_handler+0x6f4/0x740 net/can/bcm.c:413
 __run_hrtimer+0x7cd/0xf00 kernel/time/hrtimer.c:1520
 __hrtimer_run_queues kernel/time/hrtimer.c:1584 [inline]
 hrtimer_run_softirq+0x3bf/0x690 kernel/time/hrtimer.c:1601
 __do_softirq+0x2ea/0x7f5 kernel/softirq.c:293

Local variable ----msg_head@bcm_tx_timeout_handler created at:
 bcm_tx_timeout_handler+0x4f/0x740 net/can/bcm.c:398
 bcm_tx_timeout_handler+0x4f/0x740 net/can/bcm.c:398

Bytes 12-15 of 50 are uninitialized
Memory access of size 50 starts at ffff888108f51800
Data copied to user address 0000000020000040
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