Hello, When running kvm 5.2 on 4.9-rt (I've yet to verify if !RT is also affected), kvm gets stuck regulary requiring a reboot. I get the hung_task warning below. Any thoughts on how to avoid this problem? Thanks! Christoph [ 2704.403272] INFO: task kvm:18206 blocked for more than 120 seconds. [ 2704.403275] Tainted: G U 4.9.268-realtime-1-prove-rt179 #2 [ 2704.403276] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2704.403278] kvm D 0 18206 12599 0x00000320 [ 2704.403281] 0000000000000086 ffff88087e268a00 ffff8801d2822840 ffffffff81e19500 [ 2704.403283] 0000000000000000 ffff88087e268a18 ffffc90019637a98 ffffffff81841438 [ 2704.403286] 0000000000000086 ffff8801d2822e38 ffff88087e268a18 ffff88087e268a00 [ 2704.403288] Call Trace: [ 2704.403293] [<ffffffff81841438>] ? __schedule+0x308/0x830 [ 2704.403295] [<ffffffff818419a9>] schedule+0x49/0xd0 [ 2704.403296] [<ffffffff8184334c>] __rt_mutex_slowlock+0x4c/0x190 [ 2704.403298] [<ffffffff81843882>] rt_mutex_slowlock_locked+0xa2/0x290 [ 2704.403300] [<ffffffff8184446b>] __down_read+0x7b/0xb0 [ 2704.403301] [<ffffffff81843070>] down_read+0x40/0x50 [ 2704.403304] [<ffffffff8129cf20>] ? ext4_direct_IO+0x2e0/0xa40 [ 2704.403305] [<ffffffff8129cf20>] ext4_direct_IO+0x2e0/0xa40 [ 2704.403308] [<ffffffff81174789>] generic_file_read_iter+0x3c9/0x7a0 [ 2704.403310] [<ffffffff81251fde>] aio_read+0xbe/0x140 [ 2704.403312] [<ffffffff8121c688>] ? __fget+0x118/0x1e0 [ 2704.403313] [<ffffffff8121c575>] ? __fget+0x5/0x1e0 [ 2704.403315] [<ffffffff8121c7ba>] ? __fdget+0x2a/0x70 [ 2704.403317] [<ffffffff81253802>] do_io_submit+0x602/0x680 [ 2704.403318] [<ffffffff81253387>] ? do_io_submit+0x187/0x680 [ 2704.403320] [<ffffffff81253890>] SyS_io_submit+0x10/0x20 [ 2704.403322] [<ffffffff81001e1b>] do_syscall_64+0x7b/0x160 [ 2704.403324] [<ffffffff81846983>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 2704.403325] INFO: lockdep is turned off. [ 2704.403327] INFO: task worker:18552 blocked for more than 120 seconds. [ 2704.403328] Tainted: G U 4.9.268-realtime-1-prove-rt179 #2 [ 2704.403329] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 2704.403330] worker D 0 18552 12599 0x00000320 [ 2704.403333] 0000000000000082 ffff88087e368a00 ffff8801d2b85080 ffff88086c0b0000 [ 2704.403335] 0000000000000000 ffff88087e368a18 ffffc9001cb63da0 ffffffff81841438 [ 2704.403338] 0000000081e08270 ffff8801d2b85678 ffff88087e368a18 ffff88087e368a00 [ 2704.403340] Call Trace: [ 2704.403341] [<ffffffff81841438>] ? __schedule+0x308/0x830 [ 2704.403343] [<ffffffff818419a9>] schedule+0x49/0xd0 [ 2704.403345] [<ffffffff81219097>] inode_dio_wait+0xa7/0xd0 [ 2704.403347] [<ffffffff810ad650>] ? wake_up_atomic_t+0x90/0x90 [ 2704.403349] [<ffffffff812cd670>] ext4_fallocate+0x480/0xe00 [ 2704.403351] [<ffffffff811f4deb>] vfs_fallocate+0x15b/0x250 [ 2704.403352] [<ffffffff811f6044>] SyS_fallocate+0x44/0x70 [ 2704.403354] [<ffffffff81001e1b>] do_syscall_64+0x7b/0x160 [ 2704.403355] [<ffffffff81846983>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb [ 2704.403357] INFO: lockdep is turned off.
