On Tue, 2019-09-10 at 11:22 -0400, Qian Cai wrote: > On Thu, 2019-09-05 at 17:08 -0400, Qian Cai wrote: > > Another data point is if change CONFIG_DEBUG_OBJECTS_TIMERS from =y to =n, it > > will also fix it. > > > > On Thu, 2019-08-22 at 17:33 -0400, Qian Cai wrote: > > > https://raw.githubusercontent.com/cailca/linux-mm/master/arm64.config > > > > > > Booting an arm64 ThunderX2 server with page_alloc.shuffle=1 [1] + > > > CONFIG_PROVE_LOCKING=y results in hanging. > > > > > > [1] https://lore.kernel.org/linux-mm/154899811208.3165233.17623209031065121886.s > > > tgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ > > > > > > ... > > > [ 125.142689][ T1] arm-smmu-v3 arm-smmu-v3.2.auto: option mask 0x2 > > > [ 125.149687][ T1] arm-smmu-v3 arm-smmu-v3.2.auto: ias 44-bit, oas 44-bit > > > (features 0x0000170d) > > > [ 125.165198][ T1] arm-smmu-v3 arm-smmu-v3.2.auto: allocated 524288 entries > > > for cmdq > > > [ 125.239425][ [ 125.251484][ T1] arm-smmu-v3 arm-smmu-v3.3.auto: option > > > mask 0x2 > > > [ 125.258233][ T1] arm-smmu-v3 arm-smmu-v3.3.auto: ias 44-bit, oas 44-bit > > > (features 0x0000170d) > > > [ 125.282750][ T1] arm-smmu-v3 arm-smmu-v3.3.auto: allocated 524288 entries > > > for cmdq > > > [ 125.320097][ T1] arm-smmu-v3 arm-smmu-v3.3.auto: allocated 524288 entries > > > for evtq > > > [ 125.332667][ T1] arm-smmu-v3 arm-smmu-v3.4.auto: option mask 0x2 > > > [ 125.339427][ T1] arm-smmu-v3 arm-smmu-v3.4.auto: ias 44-bit, oas 44-bit > > > (features 0x0000170d) > > > [ 125.354846][ T1] arm-smmu-v3 arm-smmu-v3.4.auto: allocated 524288 entries > > > for cmdq > > > [ 125.375295][ T1] arm-smmu-v3 arm-smmu-v3.4.auto: allocated 524288 entries > > > for evtq > > > [ 125.387371][ T1] arm-smmu-v3 arm-smmu-v3.5.auto: option mask 0x2 > > > [ 125.393955][ T1] arm-smmu-v3 arm-smmu-v3.5.auto: ias 44-bit, oas 44-bit > > > (features 0x0000170d) > > > [ 125.522605][ T1] arm-smmu-v3 arm-smmu-v3.5.auto: allocated 524288 entries > > > for cmdq > > > [ 125.543338][ T1] arm-smmu-v3 arm-smmu-v3.5.auto: allocated 524288 entries > > > for evtq > > > [ 126.694742][ T1] EFI Variables Facility v0.08 2004-May-17 > > > [ 126.799291][ T1] NET: Registered protocol family 17 > > > [ 126.978632][ T1] zswap: loaded using pool lzo/zbud > > > [ 126.989168][ T1] kmemleak: Kernel memory leak detector initialized > > > [ 126.989191][ T1577] kmemleak: Automatic memory scanning thread started > > > [ 127.044079][ T1335] pcieport 0000:0f:00.0: Adding to iommu group 0 > > > [ 127.388074][ T1] Freeing unused kernel memory: 22528K > > > [ 133.527005][ T1] Checked W+X mappings: passed, no W+X pages found > > > [ 133.533474][ T1] Run /init as init process > > > [ 133.727196][ T1] systemd[1]: System time before build time, advancing > > > clock. > > > [ 134.576021][ T1587] modprobe (1587) used greatest stack depth: 27056 bytes > > > left > > > [ 134.764026][ T1] systemd[1]: systemd 239 running in system mode. (+PAM > > > +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT > > > +GNUTLS +ACL +XZ +LZ4 +SECCOMP +BLKID +ELFUTILS +KMOD +IDN2 -IDN +PCRE2 default- > > > hierarchy=legacy) > > > [ 134.799044][ T1] systemd[1]: Detected architecture arm64. > > > [ 134.804818][ T1] systemd[1]: Running in initial RAM disk. > > > <...hang...> > > > > > > Fix it by either set page_alloc.shuffle=0 or CONFIG_PROVE_LOCKING=n which allow > > > it to continue successfully. > > > > > > > > > [ 121.093846][ T1] systemd[1]: Set hostname to <hpe-apollo-cn99xx>. > > > [ 123.157524][ T1] random: systemd: uninitialized urandom read (16 bytes > > > read) > > > [ 123.168562][ T1] systemd[1]: Listening on Journal Socket. > > > [ OK ] Listening on Journal Socket. > > > [ 123.203932][ T1] random: systemd: uninitialized urandom read (16 bytes > > > read) > > > [ 123.212813][ T1] systemd[1]: Listening on udev Kernel Socket. > > > [ OK ] Listening on udev Kernel Socket. > > > ... > > Not sure if the arm64 hang is just an effect of the potential console deadlock > below. The lockdep splat can be reproduced by set, > > CONFIG_DEBUG_OBJECTS_TIMER=n (=y will lead to the hang above) > CONFIG_PROVE_LOCKING=y > CONFIG_SLAB_FREELIST_RANDOM=y (with page_alloc.shuffle=1) > > while compiling kernels, This is more than likely, as this debug patch alone will fix the hang, diff --git a/drivers/char/random.c b/drivers/char/random.c index 9b54cdb301d3..4d5c38035f03 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2323,7 +2323,7 @@ u64 get_random_u64(void) return ret; #endif - warn_unseeded_randomness(&previous); + //warn_unseeded_randomness(&previous); batch = raw_cpu_ptr(&batched_entropy_u64); spin_lock_irqsave(&batch->batch_lock, flags); which mostly indicates that the additional printk() from this path due to "page_alloc.shuffle=1" causes a real deadlock, allocate_slab shuffle_freelist get_random_u64 warn_unseeded_randomness printk > > [ 1078.214683][T43784] WARNING: possible circular locking dependency detected > [ 1078.221550][T43784] 5.3.0-rc7-next-20190904 #14 Not tainted > [ 1078.227112][T43784] ------------------------------------------------------ > [ 1078.233976][T43784] vi/43784 is trying to acquire lock: > [ 1078.239192][T43784] ffff008b7cff9290 (&(&zone->lock)->rlock){-.-.}, at: > rmqueue_bulk.constprop.21+0xb0/0x1218 > [ 1078.249111][T43784] > [ 1078.249111][T43784] but task is already holding lock: > [ 1078.256322][T43784] ffff00938db47d40 (&(&port->lock)->rlock){-.-.}, at: > pty_write+0x78/0x100 > [ 1078.264760][T43784] > [ 1078.264760][T43784] which lock already depends on the new lock. > [ 1078.264760][T43784] > [ 1078.275008][T43784] > [ 1078.275008][T43784] the existing dependency chain (in reverse order) is: > [ 1078.283869][T43784] > [ 1078.283869][T43784] -> #3 (&(&port->lock)->rlock){-.-.}: > [ 1078.291350][T43784] __lock_acquire+0x5c8/0xbb0 > [ 1078.296394][T43784] lock_acquire+0x154/0x428 > [ 1078.301266][T43784] _raw_spin_lock_irqsave+0x80/0xa0 > [ 1078.306831][T43784] tty_port_tty_get+0x28/0x68 > [ 1078.311873][T43784] tty_port_default_wakeup+0x20/0x40 > [ 1078.317523][T43784] tty_port_tty_wakeup+0x38/0x48 > [ 1078.322827][T43784] uart_write_wakeup+0x2c/0x50 > [ 1078.327956][T43784] pl011_tx_chars+0x240/0x260 > [ 1078.332999][T43784] pl011_start_tx+0x24/0xa8 > [ 1078.337868][T43784] __uart_start+0x90/0xa0 > [ 1078.342563][T43784] uart_write+0x15c/0x2c8 > [ 1078.347261][T43784] do_output_char+0x1c8/0x2b0 > [ 1078.352304][T43784] n_tty_write+0x300/0x668 > [ 1078.357087][T43784] tty_write+0x2e8/0x430 > [ 1078.361696][T43784] redirected_tty_write+0xcc/0xe8 > [ 1078.367086][T43784] do_iter_write+0x228/0x270 > [ 1078.372041][T43784] vfs_writev+0x10c/0x1c8 > [ 1078.376735][T43784] do_writev+0xdc/0x180 > [ 1078.381257][T43784] __arm64_sys_writev+0x50/0x60 > [ 1078.386476][T43784] el0_svc_handler+0x11c/0x1f0 > [ 1078.391606][T43784] el0_svc+0x8/0xc > [ 1078.395691][T43784] > [ 1078.395691][T43784] -> #2 (&port_lock_key){-.-.}: > [ 1078.402561][T43784] __lock_acquire+0x5c8/0xbb0 > [ 1078.407604][T43784] lock_acquire+0x154/0x428 > [ 1078.412474][T43784] _raw_spin_lock+0x68/0x88 > [ 1078.417343][T43784] pl011_console_write+0x2ac/0x318 > [ 1078.422820][T43784] console_unlock+0x3c4/0x898 > [ 1078.427863][T43784] vprintk_emit+0x2d4/0x460 > [ 1078.432732][T43784] vprintk_default+0x48/0x58 > [ 1078.437688][T43784] vprintk_func+0x194/0x250 > [ 1078.442557][T43784] printk+0xbc/0xec > [ 1078.446732][T43784] register_console+0x4a8/0x580 > [ 1078.451947][T43784] uart_add_one_port+0x748/0x878 > [ 1078.457250][T43784] pl011_register_port+0x98/0x128 > [ 1078.462639][T43784] sbsa_uart_probe+0x398/0x480 > [ 1078.467772][T43784] platform_drv_probe+0x70/0x108 > [ 1078.473075][T43784] really_probe+0x15c/0x5d8 > [ 1078.477944][T43784] driver_probe_device+0x94/0x1d0 > [ 1078.483335][T43784] __device_attach_driver+0x11c/0x1a8 > [ 1078.489072][T43784] bus_for_each_drv+0xf8/0x158 > [ 1078.494201][T43784] __device_attach+0x164/0x240 > [ 1078.499331][T43784] device_initial_probe+0x24/0x30 > [ 1078.504721][T43784] bus_probe_device+0xf0/0x100 > [ 1078.509850][T43784] device_add+0x63c/0x960 > [ 1078.514546][T43784] platform_device_add+0x1ac/0x3b8 > [ 1078.520023][T43784] platform_device_register_full+0x1fc/0x290 > [ 1078.526373][T43784] acpi_create_platform_device.part.0+0x264/0x3a8 > [ 1078.533152][T43784] acpi_create_platform_device+0x68/0x80 > [ 1078.539150][T43784] acpi_default_enumeration+0x34/0x78 > [ 1078.544887][T43784] acpi_bus_attach+0x340/0x3b8 > [ 1078.550015][T43784] acpi_bus_attach+0xf8/0x3b8 > [ 1078.555057][T43784] acpi_bus_attach+0xf8/0x3b8 > [ 1078.560099][T43784] acpi_bus_attach+0xf8/0x3b8 > [ 1078.565142][T43784] acpi_bus_scan+0x9c/0x100 > [ 1078.570015][T43784] acpi_scan_init+0x16c/0x320 > [ 1078.575058][T43784] acpi_init+0x330/0x3b8 > [ 1078.579666][T43784] do_one_initcall+0x158/0x7ec > [ 1078.584797][T43784] kernel_init_freeable+0x9a8/0xa70 > [ 1078.590360][T43784] kernel_init+0x18/0x138 > [ 1078.595055][T43784] ret_from_fork+0x10/0x1c > [ 1078.599835][T43784] > [ 1078.599835][T43784] -> #1 (console_owner){-...}: > [ 1078.606618][T43784] __lock_acquire+0x5c8/0xbb0 > [ 1078.611661][T43784] lock_acquire+0x154/0x428 > [ 1078.616530][T43784] console_unlock+0x298/0x898 > [ 1078.621573][T43784] vprintk_emit+0x2d4/0x460 > [ 1078.626442][T43784] vprintk_default+0x48/0x58 > [ 1078.631398][T43784] vprintk_func+0x194/0x250 > [ 1078.636267][T43784] printk+0xbc/0xec > [ 1078.640443][T43784] _warn_unseeded_randomness+0xb4/0xd0 > [ 1078.646267][T43784] get_random_u64+0x4c/0x100 > [ 1078.651224][T43784] add_to_free_area_random+0x168/0x1a0 > [ 1078.657047][T43784] free_one_page+0x3dc/0xd08 > [ 1078.662003][T43784] __free_pages_ok+0x490/0xd00 > [ 1078.667132][T43784] __free_pages+0xc4/0x118 > [ 1078.671914][T43784] __free_pages_core+0x2e8/0x428 > [ 1078.677219][T43784] memblock_free_pages+0xa4/0xec > [ 1078.682522][T43784] memblock_free_all+0x264/0x330 > [ 1078.687825][T43784] mem_init+0x90/0x148 > [ 1078.692259][T43784] start_kernel+0x368/0x684 > [ 1078.697126][T43784] > [ 1078.697126][T43784] -> #0 (&(&zone->lock)->rlock){-.-.}: > [ 1078.704604][T43784] check_prev_add+0x120/0x1138 > [ 1078.709733][T43784] validate_chain+0x888/0x1270 > [ 1078.714863][T43784] __lock_acquire+0x5c8/0xbb0 > [ 1078.719906][T43784] lock_acquire+0x154/0x428 > [ 1078.724776][T43784] _raw_spin_lock+0x68/0x88 > [ 1078.729645][T43784] rmqueue_bulk.constprop.21+0xb0/0x1218 > [ 1078.735643][T43784] get_page_from_freelist+0x898/0x24a0 > [ 1078.741467][T43784] __alloc_pages_nodemask+0x2a8/0x1d08 > [ 1078.747291][T43784] alloc_pages_current+0xb4/0x150 > [ 1078.752682][T43784] allocate_slab+0xab8/0x2350 > [ 1078.757725][T43784] new_slab+0x98/0xc0 > [ 1078.762073][T43784] ___slab_alloc+0x66c/0xa30 > [ 1078.767029][T43784] __slab_alloc+0x68/0xc8 > [ 1078.771725][T43784] __kmalloc+0x3d4/0x658 > [ 1078.776333][T43784] __tty_buffer_request_room+0xd4/0x220 > [ 1078.782244][T43784] tty_insert_flip_string_fixed_flag+0x6c/0x128 > [ 1078.788849][T43784] pty_write+0x98/0x100 > [ 1078.793370][T43784] n_tty_write+0x2a0/0x668 > [ 1078.798152][T43784] tty_write+0x2e8/0x430 > [ 1078.802760][T43784] __vfs_write+0x5c/0xb0 > [ 1078.807368][T43784] vfs_write+0xf0/0x230 > [ 1078.811890][T43784] ksys_write+0xd4/0x180 > [ 1078.816498][T43784] __arm64_sys_write+0x4c/0x60 > [ 1078.821627][T43784] el0_svc_handler+0x11c/0x1f0 > [ 1078.826756][T43784] el0_svc+0x8/0xc > [ 1078.830842][T43784] > [ 1078.830842][T43784] other info that might help us debug this: > [ 1078.830842][T43784] > [ 1078.840918][T43784] Chain exists of: > [ 1078.840918][T43784] &(&zone->lock)->rlock --> &port_lock_key --> &(&port- > > lock)->rlock > > [ 1078.840918][T43784] > [ 1078.854731][T43784] Possible unsafe locking scenario: > [ 1078.854731][T43784] > [ 1078.862029][T43784] CPU0 CPU1 > [ 1078.867243][T43784] ---- ---- > [ 1078.872457][T43784] lock(&(&port->lock)->rlock); > [ 1078.877238][T43784] lock(&port_lock_key); > [ 1078.883929][T43784] lock(&(&port->lock)- > > rlock); > > [ 1078.891228][T43784] lock(&(&zone->lock)->rlock); > [ 1078.896010][T43784] > [ 1078.896010][T43784] *** DEADLOCK *** > [ 1078.896010][T43784] > [ 1078.904004][T43784] 5 locks held by vi/43784: > [ 1078.908351][T43784] #0: ffff000c36240890 (&tty->ldisc_sem){++++}, at: > ldsem_down_read+0x44/0x50 > [ 1078.917133][T43784] #1: ffff000c36240918 (&tty->atomic_write_lock){+.+.}, > at: tty_write_lock+0x24/0x60 > [ 1078.926521][T43784] #2: ffff000c36240aa0 (&o_tty->termios_rwsem/1){++++}, > at: n_tty_write+0x108/0x668 > [ 1078.935823][T43784] #3: ffffa0001e0b2360 (&ldata->output_lock){+.+.}, at: > n_tty_write+0x1d0/0x668 > [ 1078.944777][T43784] #4: ffff00938db47d40 (&(&port->lock)->rlock){-.-.}, at: > pty_write+0x78/0x100 > [ 1078.953644][T43784] > [ 1078.953644][T43784] stack backtrace: > [ 1078.959382][T43784] CPU: 97 PID: 43784 Comm: vi Not tainted 5.3.0-rc7-next- > 20190904 #14 > [ 1078.967376][T43784] Hardware name: HPE Apollo > 70 /C01_APACHE_MB , BIOS L50_5.13_1.11 06/18/2019 > [ 1078.977799][T43784] Call trace: > [ 1078.980932][T43784] dump_backtrace+0x0/0x228 > [ 1078.985279][T43784] show_stack+0x24/0x30 > [ 1078.989282][T43784] dump_stack+0xe8/0x13c > [ 1078.993370][T43784] print_circular_bug+0x334/0x3d8 > [ 1078.998240][T43784] check_noncircular+0x268/0x310 > [ 1079.003022][T43784] check_prev_add+0x120/0x1138 > [ 1079.007631][T43784] validate_chain+0x888/0x1270 > [ 1079.012241][T43784] __lock_acquire+0x5c8/0xbb0 > [ 1079.016763][T43784] lock_acquire+0x154/0x428 > [ 1079.021111][T43784] _raw_spin_lock+0x68/0x88 > [ 1079.025460][T43784] rmqueue_bulk.constprop.21+0xb0/0x1218 > [ 1079.030937][T43784] get_page_from_freelist+0x898/0x24a0 > [ 1079.036240][T43784] __alloc_pages_nodemask+0x2a8/0x1d08 > [ 1079.041542][T43784] alloc_pages_current+0xb4/0x150 > [ 1079.046412][T43784] allocate_slab+0xab8/0x2350 > [ 1079.050934][T43784] new_slab+0x98/0xc0 > [ 1079.054761][T43784] ___slab_alloc+0x66c/0xa30 > [ 1079.059196][T43784] __slab_alloc+0x68/0xc8 > [ 1079.063371][T43784] __kmalloc+0x3d4/0x658 > [ 1079.067458][T43784] __tty_buffer_request_room+0xd4/0x220 > [ 1079.072847][T43784] tty_insert_flip_string_fixed_flag+0x6c/0x128 > [ 1079.078932][T43784] pty_write+0x98/0x100 > [ 1079.082932][T43784] n_tty_write+0x2a0/0x668 > [ 1079.087193][T43784] tty_write+0x2e8/0x430 > [ 1079.091280][T43784] __vfs_write+0x5c/0xb0 > [ 1079.095367][T43784] vfs_write+0xf0/0x230 > [ 1079.099368][T43784] ksys_write+0xd4/0x180 > [ 1079.103455][T43784] __arm64_sys_write+0x4c/0x60 > [ 1079.108064][T43784] el0_svc_handler+0x11c/0x1f0 > [ 1079.112672][T43784] el0_svc+0x8/0xc
