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BUG: KCSAN: data-race in random_recv_done / virtio_read

write to 0xffff888101ebfeec of 4 bytes by task 8087 on cpu 0:
 request_entropy drivers/char/hw_random/virtio-rng.c:56 [inline]
 copy_data drivers/char/hw_random/virtio-rng.c:74 [inline]
 virtio_read+0x190/0x440 drivers/char/hw_random/virtio-rng.c:92
 rng_get_data drivers/char/hw_random/core.c:198 [inline]
 rng_dev_read+0x1b4/0x630 drivers/char/hw_random/core.c:235
 vfs_read+0x198/0x560 fs/read_write.c:468
 ksys_read+0xe8/0x1a0 fs/read_write.c:613
 __do_sys_read fs/read_write.c:623 [inline]
 __se_sys_read fs/read_write.c:621 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:621
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

write to 0xffff888101ebfeec of 4 bytes by interrupt on cpu 1:
 random_recv_done+0x5e/0x80 drivers/char/hw_random/virtio-rng.c:45
 vring_interrupt+0x14c/0x170 drivers/virtio/virtio_ring.c:2470
 __handle_irq_event_percpu+0x92/0x400 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0x60/0xf0 kernel/irq/handle.c:210
 handle_edge_irq+0x17e/0x5a0 kernel/irq/chip.c:819
 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline]
 handle_irq arch/x86/kernel/irq.c:231 [inline]
 __common_interrupt+0x60/0x100 arch/x86/kernel/irq.c:250
 common_interrupt+0x9a/0xc0 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x22/0x40 arch/x86/include/asm/idtentry.h:640
 arch_atomic_add_return kernel/locking/spinlock.c:259 [inline]
 arch_atomic_sub_return arch/x86/include/asm/atomic.h:178 [inline]
 atomic_sub_return_release include/linux/atomic/atomic-instrumented.h:147 [inline]
 queued_read_unlock include/asm-generic/qrwlock.h:113 [inline]
 __raw_read_unlock include/linux/rwlock_api_smp.h:232 [inline]
 _raw_read_unlock+0x9/0x30 kernel/locking/spinlock.c:260
 start_this_handle+0x103f/0x1130 fs/jbd2/transaction.c:460
 jbd2__journal_start+0x1d1/0x3b0 fs/jbd2/transaction.c:520
 __ext4_journal_start_sb+0x159/0x300 fs/ext4/ext4_jbd2.c:105
 __ext4_journal_start fs/ext4/ext4_jbd2.h:326 [inline]
 ext4_dirty_inode+0x58/0xa0 fs/ext4/inode.c:6007
 __mark_inode_dirty+0x15b/0x730 fs/fs-writeback.c:2408
 mark_inode_dirty include/linux/fs.h:2475 [inline]
 generic_write_end+0x175/0x350 fs/buffer.c:2184
 ext4_da_write_end+0x26c/0x620 fs/ext4/inode.c:3096
 generic_perform_write+0x264/0x3f0 mm/filemap.c:3764
 ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:285
 ext4_file_write_iter+0x2c7/0x1170
 call_write_iter include/linux/fs.h:2199 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x468/0x760 fs/read_write.c:584
 ksys_write+0xe8/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000040 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8064 Comm: syz-executor.5 Tainted: G        W          6.1.0-rc8-syzkaller-00148-g0d1409e4ff08-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
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virtio_rng virtio3: input:id 1 is not a head!