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BUG: KMSAN: uninit-value in copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
BUG: KMSAN: uninit-value in raw_copy_to_user arch/x86/include/asm/uaccess_64.h:128 [inline]
BUG: KMSAN: uninit-value in _copy_to_user+0x214/0x230 lib/usercopy.c:30
CPU: 0 PID: 6584 Comm: syz-executor275 Not tainted 4.19.0+ #77
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+0x32d/0x480 lib/dump_stack.c:113
 kmsan_report+0x1a2/0x2e0 mm/kmsan/kmsan.c:911
 __msan_warning+0x74/0xd0 mm/kmsan/kmsan_instr.c:415
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:128 [inline]
 _copy_to_user+0x214/0x230 lib/usercopy.c:30
 copy_to_user include/linux/uaccess.h:183 [inline]
 __vb2_perform_fileio+0x5d8/0x23c0 drivers/media/common/videobuf2/videobuf2-core.c:2419
 vb2_read+0xf7/0x110 drivers/media/common/videobuf2/videobuf2-core.c:2493
 vb2_fop_read+0x475/0x640 drivers/media/common/videobuf2/videobuf2-v4l2.c:898
 v4l2_read+0x274/0x4a0 drivers/media/v4l2-core/v4l2-dev.c:317
 __vfs_read+0x1e2/0xb10 fs/read_write.c:416
 vfs_read+0x380/0x6b0 fs/read_write.c:452
 ksys_read fs/read_write.c:578 [inline]
 __do_sys_read fs/read_write.c:588 [inline]
 __se_sys_read+0x17a/0x370 fs/read_write.c:586
 __x64_sys_read+0x4a/0x70 fs/read_write.c:586
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x444b49
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 2b ce fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe5d72b728 EFLAGS: 00000213 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000444b49
RDX: 0000000000000059 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000001bed880 R09: 00000000004002e0
R10: 000000000000000f R11: 0000000000000213 R12: 0000000000401e00
R13: 0000000000401e90 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1e0 mm/kmsan/kmsan.c:177
 kmsan_kmalloc+0x98/0x110 mm/kmsan/kmsan_hooks.c:104
 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:113
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2727 [inline]
 __kmalloc_node_track_caller+0xf62/0x14e0 mm/slub.c:4360
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x42b/0xeb0 net/core/skbuff.c:206
 alloc_skb_fclone include/linux/skbuff.h:1038 [inline]
 sk_stream_alloc_skb+0x236/0xe60 net/ipv4/tcp.c:874
 tcp_sendmsg_locked+0x2638/0x6c30 net/ipv4/tcp.c:1286
 tcp_sendmsg+0xb2/0x100 net/ipv4/tcp.c:1443
 inet_sendmsg+0x4e9/0x800 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 sock_write_iter+0x404/0x4e0 net/socket.c:900
 call_write_iter include/linux/fs.h:1808 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x882/0xb80 fs/read_write.c:487
 vfs_write+0x4a3/0x8f0 fs/read_write.c:549
 ksys_write fs/read_write.c:598 [inline]
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write+0x17a/0x370 fs/read_write.c:607
 __x64_sys_write+0x4a/0x70 fs/read_write.c:607
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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