=====================================================
BUG: KMSAN: uninit-value in do_user_addr_fault+0x7ff/0x1f80 arch/x86/mm/fault.c:1333
 do_user_addr_fault+0x7ff/0x1f80 arch/x86/mm/fault.c:1333
 handle_page_fault arch/x86/mm/fault.c:1495 [inline]
 __exc_page_fault+0x92/0x1c0 arch/x86/mm/fault.c:1551
 exc_page_fault+0x25/0x30 arch/x86/mm/fault.c:1507
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:605
 __put_user_nocheck_4+0x3/0x11
 __compat_sys_sendmmsg net/compat.c:361 [inline]
 __do_compat_sys_sendmmsg net/compat.c:368 [inline]
 __se_compat_sys_sendmmsg net/compat.c:365 [inline]
 __ia32_compat_sys_sendmmsg+0x127/0x180 net/compat.c:365
 do_syscall_32_irqs_on arch/x86/entry/common.c:84 [inline]
 __do_fast_syscall_32+0x96/0xe0 arch/x86/entry/common.c:149
 do_fast_syscall_32+0x3c/0x80 arch/x86/entry/common.c:179
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:222
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable ----regs@__bpf_prog_run32 created at:
 __bpf_prog_run32+0x84/0x180 kernel/bpf/core.c:1741
 bpf_dispatcher_nop_func include/linux/bpf.h:684 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:1780 [inline]
 bpf_trace_run5+0x1ec/0x480 kernel/trace/bpf_trace.c:1820
=====================================================
Kernel panic - not syncing: panic_on_kmsan set ...
CPU: 1 PID: 12347 Comm: syz-executor.3 Tainted: G    B             5.13.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x25a/0x2f6 lib/dump_stack.c:120
 panic+0x4c7/0xe98 kernel/panic.c:231
 kmsan_report+0x2ee/0x300 mm/kmsan/report.c:179
 __msan_warning+0xd7/0x150 mm/kmsan/instrumentation.c:208
 do_user_addr_fault+0x7ff/0x1f80 arch/x86/mm/fault.c:1333
 handle_page_fault arch/x86/mm/fault.c:1495 [inline]
 __exc_page_fault+0x92/0x1c0 arch/x86/mm/fault.c:1551
 exc_page_fault+0x25/0x30 arch/x86/mm/fault.c:1507
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:605
RIP: 0010:__put_user_nocheck_4+0x3/0x11
Code: 00 00 48 39 d9 73 54 0f 1f 00 66 89 01 31 c9 0f 1f 00 c3 0f 1f 44 00 00 48 bb fd ef ff ff ff 7f 00 00 48 39 d9 73 34 0f 1f 00 <89> 01 31 c9 0f 1f 00 c3 66 0f 1f 44 00 00 48 bb f9 ef ff ff ff 7f
RSP: 0018:ffff8881690d3b68 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000020002ddc RCX: 0000000020002ddc
RDX: 0000000020002dc0 RSI: 00000000000000c7 RDI: 00000000000000c8
RBP: ffff8881690d3e70 R08: ffffffff8c4f0e47 R09: ffff88813fffa000
R10: 0000000024a47f65 R11: 0000000090e74b84 R12: ffff8881690d3b70
R13: 0000000000000000 R14: ffff8880a877e908 R15: 0000000006d80149
 __compat_sys_sendmmsg net/compat.c:361 [inline]
 __do_compat_sys_sendmmsg net/compat.c:368 [inline]
 __se_compat_sys_sendmmsg net/compat.c:365 [inline]
 __ia32_compat_sys_sendmmsg+0x127/0x180 net/compat.c:365
 do_syscall_32_irqs_on arch/x86/entry/common.c:84 [inline]
 __do_fast_syscall_32+0x96/0xe0 arch/x86/entry/common.c:149
 do_fast_syscall_32+0x3c/0x80 arch/x86/entry/common.c:179
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:222
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf6f58549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f45525fc EFLAGS: 00000296 ORIG_RAX: 0000000000000159
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000020002dc0
RDX: 00000000db7a66cb RSI: 0000000000003ec0 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	48 39 d9             	cmp    %rbx,%rcx
   5:	73 54                	jae    0x5b
   7:	0f 1f 00             	nopl   (%rax)
   a:	66 89 01             	mov    %ax,(%rcx)
   d:	31 c9                	xor    %ecx,%ecx
   f:	0f 1f 00             	nopl   (%rax)
  12:	c3                   	retq
  13:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
  18:	48 bb fd ef ff ff ff 	movabs $0x7fffffffeffd,%rbx
  1f:	7f 00 00
  22:	48 39 d9             	cmp    %rbx,%rcx
  25:	73 34                	jae    0x5b
  27:	0f 1f 00             	nopl   (%rax)
* 2a:	89 01                	mov    %eax,(%rcx) <-- trapping instruction
  2c:	31 c9                	xor    %ecx,%ecx
  2e:	0f 1f 00             	nopl   (%rax)
  31:	c3                   	retq
  32:	66 0f 1f 44 00 00    	nopw   0x0(%rax,%rax,1)
  38:	48                   	rex.W
  39:	bb f9 ef ff ff       	mov    $0xffffeff9,%ebx
  3e:	ff                   	(bad)
  3f:	7f                   	.byte 0x7f