https://bugzilla.kernel.org/show_bug.cgi?id=202349 --- Comment #12 from nfxjfg@xxxxxxxxxxxxxx --- So I tried on the following kernel versions: 4.19.19 4.19.16 4.19.0 4.18.20 4.16.14 It happened on all of them. Reproduction is a bit spotty. The script I first posted doesn't work reliably anymore. I guess it depends on the kind and amount of memory pressure. Despite hard reproduction, it's not an obscure issue. I've also hit it when compiling the kernel on a XFS filesystem on a hard disk. My reproduction steps are now as following (and yes they're absurd): - run memtester 12G (make sure "free memory" as shown in top goes to very low while running the test) - start video playback (I used mpv with some random 720p video) - run test.sh (maybe until 100k files) - run sync - run rm -rf /mnt/tmp1/tests/ - switch to another virtual desktop with lots of firefox windows (yeah...), and switch back - video playback gets noticeably interrupted for a moment This happened even on 4.16.14. dmesg except when I "caught" it again on 4.19.19 (there's nothing new I guess): [ 250.656494] sysrq: SysRq : Show Blocked State [ 250.656505] task PC stack pid father [ 250.656581] kswapd0 D 0 91 2 0x80000000 [ 250.656585] Call Trace: [ 250.656600] ? __schedule+0x23d/0x830 [ 250.656604] schedule+0x28/0x80 [ 250.656608] schedule_timeout+0x23e/0x360 [ 250.656612] wait_for_completion+0xeb/0x150 [ 250.656617] ? wake_up_q+0x70/0x70 [ 250.656623] ? __xfs_buf_submit+0x112/0x230 [ 250.656625] ? xfs_bwrite+0x25/0x60 [ 250.656628] xfs_buf_iowait+0x22/0xc0 [ 250.656631] __xfs_buf_submit+0x112/0x230 [ 250.656633] xfs_bwrite+0x25/0x60 [ 250.656637] xfs_reclaim_inode+0x2e5/0x310 [ 250.656640] xfs_reclaim_inodes_ag+0x19e/0x2d0 [ 250.656645] xfs_reclaim_inodes_nr+0x31/0x40 [ 250.656650] super_cache_scan+0x14c/0x1a0 [ 250.656656] do_shrink_slab+0x129/0x270 [ 250.656660] shrink_slab+0x201/0x280 [ 250.656663] shrink_node+0xd6/0x420 [ 250.656666] kswapd+0x3d3/0x6c0 [ 250.656670] ? mem_cgroup_shrink_node+0x140/0x140 [ 250.656674] kthread+0x110/0x130 [ 250.656677] ? kthread_create_worker_on_cpu+0x40/0x40 [ 250.656680] ret_from_fork+0x24/0x30 [ 250.656785] Xorg D 0 850 836 0x00400004 [ 250.656789] Call Trace: [ 250.656792] ? __schedule+0x23d/0x830 [ 250.656795] schedule+0x28/0x80 [ 250.656798] schedule_preempt_disabled+0xa/0x10 [ 250.656801] __mutex_lock.isra.5+0x28b/0x460 [ 250.656806] ? xfs_perag_get_tag+0x2d/0xc0 [ 250.656808] xfs_reclaim_inodes_ag+0x286/0x2d0 [ 250.656811] ? isolate_lru_pages.isra.55+0x34f/0x400 [ 250.656817] ? list_lru_add+0xb2/0x190 [ 250.656819] ? list_lru_isolate_move+0x40/0x60 [ 250.656824] ? iput+0x1f0/0x1f0 [ 250.656827] xfs_reclaim_inodes_nr+0x31/0x40 [ 250.656829] super_cache_scan+0x14c/0x1a0 [ 250.656832] do_shrink_slab+0x129/0x270 [ 250.656836] shrink_slab+0x144/0x280 [ 250.656838] shrink_node+0xd6/0x420 [ 250.656841] do_try_to_free_pages+0xb6/0x350 [ 250.656844] try_to_free_pages+0xce/0x180 [ 250.656856] __alloc_pages_slowpath+0x347/0xc70 [ 250.656863] __alloc_pages_nodemask+0x25c/0x280 [ 250.656875] ttm_pool_populate+0x25e/0x480 [ttm] [ 250.656880] ? kmalloc_large_node+0x37/0x60 [ 250.656883] ? __kmalloc_node+0x204/0x2a0 [ 250.656891] ttm_populate_and_map_pages+0x24/0x250 [ttm] [ 250.656899] ttm_tt_populate.part.9+0x1b/0x60 [ttm] [ 250.656907] ttm_tt_bind+0x42/0x60 [ttm] [ 250.656915] ttm_bo_handle_move_mem+0x258/0x4e0 [ttm] [ 250.656995] ? amdgpu_bo_subtract_pin_size+0x50/0x50 [amdgpu] [ 250.657003] ttm_bo_validate+0xe7/0x110 [ttm] [ 250.657079] ? amdgpu_bo_subtract_pin_size+0x50/0x50 [amdgpu] [ 250.657105] ? drm_vma_offset_add+0x46/0x50 [drm] [ 250.657113] ttm_bo_init_reserved+0x342/0x380 [ttm] [ 250.657189] amdgpu_bo_do_create+0x19c/0x400 [amdgpu] [ 250.657266] ? amdgpu_bo_subtract_pin_size+0x50/0x50 [amdgpu] [ 250.657269] ? try_to_wake_up+0x44/0x450 [ 250.657343] amdgpu_bo_create+0x30/0x200 [amdgpu] [ 250.657349] ? cpumask_next_wrap+0x2c/0x70 [ 250.657352] ? sched_clock_cpu+0xc/0xb0 [ 250.657355] ? select_idle_sibling+0x293/0x3a0 [ 250.657431] amdgpu_gem_object_create+0x8b/0x110 [amdgpu] [ 250.657509] amdgpu_gem_create_ioctl+0x1d0/0x290 [amdgpu] [ 250.657516] ? tracing_record_taskinfo_skip+0x40/0x50 [ 250.657518] ? tracing_record_taskinfo+0xe/0xa0 [ 250.657594] ? amdgpu_gem_object_close+0x1c0/0x1c0 [amdgpu] [ 250.657614] drm_ioctl_kernel+0x7f/0xd0 [drm] [ 250.657619] ? sock_sendmsg+0x30/0x40 [ 250.657639] drm_ioctl+0x1e4/0x380 [drm] [ 250.657715] ? amdgpu_gem_object_close+0x1c0/0x1c0 [amdgpu] [ 250.657720] ? do_futex+0x2a1/0xa30 [ 250.657802] amdgpu_drm_ioctl+0x49/0x80 [amdgpu] [ 250.657828] do_vfs_ioctl+0x8d/0x5d0 [ 250.657832] ? __x64_sys_futex+0x133/0x15b [ 250.657835] ksys_ioctl+0x60/0x90 [ 250.657838] __x64_sys_ioctl+0x16/0x20 [ 250.657842] do_syscall_64+0x4a/0xd0 [ 250.657845] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 250.657849] RIP: 0033:0x7f12b52dc747 [ 250.657855] Code: Bad RIP value. [ 250.657856] RSP: 002b:00007ffceccab168 EFLAGS: 00003246 ORIG_RAX: 0000000000000010 [ 250.657860] RAX: ffffffffffffffda RBX: 00007ffceccab250 RCX: 00007f12b52dc747 [ 250.657861] RDX: 00007ffceccab1c0 RSI: 00000000c0206440 RDI: 000000000000000e [ 250.657863] RBP: 00007ffceccab1c0 R08: 0000559b8f644890 R09: 00007f12b53a7cb0 [ 250.657864] R10: 0000559b8e72a010 R11: 0000000000003246 R12: 00000000c0206440 [ 250.657865] R13: 000000000000000e R14: 0000559b8e7bf500 R15: 0000559b8f644890 Also I noticed some more bad behavior. When I copied hundreds of gigabytes from a SSD block device to a XFS file system on a HDD, I got _severe_ problems with tasks hanging. They got stuck in something like io_scheduler (I don't think I have the log anymore; could probably reproduce if needed). This was also a "desktop randomly freezes on heavy background I/O". Although the freezes were worse (waiting for up to a minute for small I/O to finish!), it's overall not as bad as the one this bug is about, because most hangs seemed to be about accesses to the same filesystem. -- You are receiving this mail because: You are watching the assignee of the bug.
