syzbot

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BUG: KCSAN: data-race in af_alg_sendpage / af_alg_wait_for_data

write to 0xffff8880755dd0d4 of 1 bytes by task 28850 on cpu 1:
 af_alg_sendpage+0x4e2/0x530 crypto/af_alg.c:1000
 kernel_sendpage net/socket.c:3642 [inline]
 sock_sendpage+0x84/0xc0 net/socket.c:945
 pipe_to_sendpage+0x128/0x160 fs/splice.c:448
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x1f7/0x4f0 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 generic_splice_sendpage+0x80/0xb0 fs/splice.c:834
 do_splice_from fs/splice.c:846 [inline]
 direct_splice_actor+0x95/0x160 fs/splice.c:1016
 splice_direct_to_actor+0x365/0x660 fs/splice.c:971
 do_splice_direct+0xf2/0x170 fs/splice.c:1059
 do_sendfile+0x562/0xb10 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1587
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880755dd0d4 of 1 bytes by task 28844 on cpu 0:
 af_alg_wait_for_data+0x158/0x270 crypto/af_alg.c:757
 _aead_recvmsg crypto/algif_aead.c:110 [inline]
 aead_recvmsg+0x271/0xd00 crypto/algif_aead.c:330
 sock_recvmsg_nosec net/socket.c:886 [inline]
 sock_recvmsg net/socket.c:904 [inline]
 sock_read_iter+0x19c/0x1e0 net/socket.c:977
 call_read_iter include/linux/fs.h:1902 [inline]
 generic_file_splice_read+0x22a/0x310 fs/splice.c:312
 sock_splice_read+0xa5/0xb0 net/socket.c:955
 do_splice_to fs/splice.c:870 [inline]
 do_splice+0xe6b/0x10c0 fs/splice.c:1179
 __do_sys_splice fs/splice.c:1419 [inline]
 __se_sys_splice fs/splice.c:1401 [inline]
 __x64_sys_splice+0xf2/0x190 fs/splice.c:1401
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28844 Comm: syz-executor.2 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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