+ John
On 2022-06-24 11:52:26 [+0200], Mike Galbraith wrote:
> On Fri, 2022-06-24 at 10:42 +0200, Sebastian Andrzej Siewior wrote:
> > On 2022-06-18 11:25:39 [+0200], Mike Galbraith wrote:
> > > I haven't done any digging to see why this now happens where it
> > > previously did not.
> >
> > I don't see where interrupts have been disabled but they have been. The
> > printk path should yell earlier but did not the crng path is kind of
> > late and I don't see anything obvious in between.
>
> Allegedly vprintk_store().
>
> (gdb) list *vprintk_store+0x3cc
> 0xffffffff8114283c is in vprintk_store (kernel/printk/printk.c:2280).
> warning: Source file is more recent than executable.
> 2275 u32 caller_id;
> 2276 u16 text_len;
> 2277 int ret = 0;
> 2278 u64 ts_nsec;
> 2279
> 2280 if (!printk_enter_irqsave(recursion_ptr, irqflags))
> 2281 return 0;
> 2282
> 2283 /*
> 2284 * Since the duration of printk() can vary depending on the message
> (gdb)
ehm. Why do we need to keep interrupts disabled for vsnprintf()?
Wouldn't it work to move that lock a few lines below where it is
actually needed?
> [ 6.520357] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
> [ 6.520358] in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 399, name: systemd-udevd
> [ 6.520359] preempt_count: 0, expected: 0
> [ 6.520359] RCU nest depth: 1, expected: 1
> [ 6.520360] 5 locks held by systemd-udevd/399:
> [ 6.520361] #0: ffff909a815821a8 (&dev->mutex){....}-{3:3}, at: __driver_attach+0xa1/0x170
> [ 6.520367] #1: ffff909a912b0a98 (&helper->lock){+.+.}-{3:3}, at: drm_fb_helper_initial_config+0x26/0x40 [drm_kms_helper]
> [ 6.520383] #2: ffffffffbd8e91b8 (filling){....}-{2:2}, at: default_pointer+0x17e/0x2d0
> [ 6.520387] #3: ffffffffbd7929a0 (rcu_read_lock){....}-{1:2}, at: rt_spin_trylock+0x36/0xd0
> [ 6.520391] #4: ffff909d8ea335a0 ((crngs.lock)){+.+.}-{2:2}, at: crng_make_state+0x76/0x1c0
> [ 6.520394] irq event stamp: 843364
> [ 6.520394] hardirqs last enabled at (843363): [<ffffffffbc7dfb10>] _raw_spin_unlock_irqrestore+0x30/0x77
> [ 6.520397] hardirqs last disabled at (843364): [<ffffffffbbd4283c>] vprintk_store+0x3cc/0x550
> [ 6.520399] softirqs last enabled at (151950): [<ffffffffbbcb8223>] __local_bh_enable_ip+0xc3/0x150
> [ 6.520401] softirqs last disabled at (151944): [<ffffffffbbe8c135>] btf_alloc_id+0x5/0xb0
> [ 6.520404] CPU: 0 PID: 399 Comm: systemd-udevd Tainted: G W E 5.19.0.gca1fdab-master-rt #5 2262f40963ee88d2873a82a86160b299ace0d165
> [ 6.520406] Hardware name: MEDION MS-7848/MS-7848, BIOS M7848W08.20C 09/23/2013
> [ 6.520407] Call Trace:
> [ 6.520408] <TASK>
> [ 6.520409] dump_stack_lvl+0x55/0x6d
> [ 6.520413] __might_resched+0x1aa/0x1e0
> [ 6.520418] rt_spin_lock+0x4d/0xe0
> [ 6.520419] ? crng_make_state+0x76/0x1c0
> [ 6.520422] crng_make_state+0x76/0x1c0
> [ 6.520426] _get_random_bytes.part.16+0x4e/0x110
> [ 6.520428] ? rt_spin_trylock+0x36/0xd0
> [ 6.520432] ? preempt_count_sub+0x43/0x50
> [ 6.520434] ? rt_spin_trylock+0x8b/0xd0
> [ 6.520435] ? rt_spin_trylock+0x8b/0xd0
> [ 6.520438] ? migrate_disable+0x119/0x120
> [ 6.520442] default_pointer+0x2a0/0x2d0
> [ 6.520448] vsnprintf+0x35a/0x4c0
> [ 6.520449] ? kernel_text_address+0xaa/0xc0
> [ 6.520454] va_format.isra.16+0x6e/0xa0
> [ 6.520459] vsnprintf+0x35a/0x4c0
> [ 6.520464] vprintk_store+0x150/0x550
> [ 6.520468] ? string+0x40/0x50
> [ 6.520472] ? vsnprintf+0x48f/0x4c0
> [ 6.520480] vprintk_emit+0x44/0x170
> [ 6.520482] ? __lock_acquire+0xb9d/0x18b0
> [ 6.520487] dev_vprintk_emit+0x185/0x1ae
> [ 6.520494] ? lock_is_held_type+0xb2/0x110
> [ 6.520499] ? dev_printk_emit+0x4a/0x66
> [ 6.520501] ? mark_held_locks+0x49/0x70
> [ 6.520502] dev_printk_emit+0x4a/0x66
> [ 6.520506] ? preempt_count_sub+0x43/0x50
> [ 6.520510] _dev_info+0x64/0x80
> [ 6.520518] nouveau_fbcon_create+0x2d4/0x500 [nouveau adfaa6c52e612d43880f223e1d4b1d7b83facd58]
> [ 6.520615] __drm_fb_helper_initial_config_and_unlock+0x336/0x5f0 [drm_kms_helper 8e2e6f207f0cb44a547a65ef3965573df1212de6]
> [ 6.520635] nouveau_fbcon_init+0x180/0x1f0 [nouveau adfaa6c52e612d43880f223e1d4b1d7b83facd58]
> [ 6.520706] nouveau_drm_device_init+0x1f7/0x860 [nouveau adfaa6c52e612d43880f223e1d4b1d7b83facd58]
> [ 6.520778] ? pci_update_current_state+0x65/0xa0
> [ 6.520785] nouveau_drm_probe+0x11b/0x220 [nouveau adfaa6c52e612d43880f223e1d4b1d7b83facd58]
> [ 6.520856] local_pci_probe+0x42/0x90
> [ 6.520860] pci_device_probe+0x176/0x240
> [ 6.520862] ? sysfs_do_create_link_sd.isra.2+0x68/0xd0
> [ 6.520869] really_probe+0x108/0x3d0
> [ 6.520873] __driver_probe_device+0x100/0x170
> [ 6.520876] driver_probe_device+0x1f/0xa0
> [ 6.520879] __driver_attach+0xac/0x170
> [ 6.520881] ? __device_attach_driver+0xe0/0xe0
> [ 6.520884] ? __device_attach_driver+0xe0/0xe0
> [ 6.520886] bus_for_each_dev+0x76/0xc0
> [ 6.520890] bus_add_driver+0x19f/0x240
> [ 6.520893] ? 0xffffffffc06ec000
> [ 6.520896] driver_register+0x5b/0xf0
> [ 6.520898] ? 0xffffffffc06ec000
> [ 6.520899] do_one_initcall+0x58/0x3d0
> [ 6.520903] ? trace_kmalloc+0xb6/0x140
> [ 6.520905] ? kmem_cache_alloc_trace+0x13c/0x1c0
> [ 6.520907] ? do_init_module+0x22/0x1fc
> [ 6.520914] do_init_module+0x4b/0x1fc
> [ 6.520918] load_module+0x18d2/0x2380
> [ 6.520936] ? __do_sys_finit_module+0xaf/0x120
> [ 6.520937] __do_sys_finit_module+0xaf/0x120
> [ 6.520948] do_syscall_64+0x58/0x80
> [ 6.520951] ? do_syscall_64+0x67/0x80
> [ 6.520953] ? lockdep_hardirqs_on_prepare+0xd8/0x170
> [ 6.520957] ? do_syscall_64+0x67/0x80
> [ 6.520958] ? do_syscall_64+0x67/0x80
> [ 6.520962] entry_SYSCALL_64_after_hwframe+0x46/0xb0
> [ 6.520965] RIP: 0033:0x7f911ee69ec9
> [ 6.520967] Code: 2e 00 b8 ca 00 00 00 0f 05 eb a5 66 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 97 7f 2d 00 f7 d8 64 89 01 48
> [ 6.520968] RSP: 002b:00007ffe6427de98 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> [ 6.520969] RAX: ffffffffffffffda RBX: 0000558cc2ab38a0 RCX: 00007f911ee69ec9
> [ 6.520970] RDX: 0000000000000000 RSI: 00007f911f7dd79d RDI: 000000000000001b
> [ 6.520971] RBP: 00007f911f7dd79d R08: 0000000000000000 R09: 0000558cc2a939a0
> [ 6.520971] R10: 000000000000001b R11: 0000000000000246 R12: 0000000000020000
> [ 6.520972] R13: 0000558cc2abec00 R14: 0000000000000000 R15: 0000558cc2ac7f80
Sebastian
