Re: [uml-devel] [PATCH v2] EPOLL Interrupt Controller V2.0

[Thomas Meyer <thomas@m3y3r.de>]

Am Montag, den 09.11.2015, 15:03 +0000 schrieb Anton Ivanov:
> It throws a couple of harmless "epoll del fd" warnings on reboot
> which 
> result the fact that disable_fd/enable_fd are not removed in the 
> terminal/line code.
> 
> These are harmless and will go away once the term/line code gets
> support 
> for real write IRQs in addition to read at some point in the future.
> 
> I have fixed the file descriptor leak in the reboot case.

Hi,

now with the list on copy!

Richard: can you make some sense out of these stack traces? I can
provide the config if you want!

I see a lot of bugs of type "BUG: spinlock recursion on CPU#0" with
this patch:

I did look over your patch and found two errors in the irq_lock
spinlock handling:

http://m3y3r.dyndns.org:9100/gerrit/#/c/2/1..2/arch/um/kernel/irq.c

But it still seems to miss something as above bugs still occurs, but
now the system boots up a bit more at least.

Example:
 [  225.570000] BUG: spinlock lockup suspected on CPU#0, chmod/516
 [  225.570000]  lock: irq_lock+0x0/0x18, .magic: dead4ead, .owner:
 [  225.570000] CPU: 0 PID: 516 Comm: chmod Not tainted 4.3.0-00010-
 g96b3e9d #100
 [  225.570000] Stack:
 [  225.570000]  69323490 6008bbd2 00000000 6b0fd580
 [  225.570000]  6083c440 600d191a 693234a0 603b8701
 [  225.570000]  693234e0 60085773 00000000 00000000
 [  225.570000] Call Trace:
 [  225.570000]  [<600d191a>] ? printk+0x0/0x94
 [  225.570000]  [<60047cc0>] ? __delay+0x0/0x30
 [  225.570000]  [<6002d84b>] show_stack+0xdb/0x1a0
 [  225.570000]  [<6008bbd2>] ? dump_stack_print_info+0xd2/0xf0
 [  225.570000]  [<600d191a>] ? printk+0x0/0x94
 [  225.570000]  [<603b8701>] dump_stack+0x2a/0x39
 [  225.570000]  [<60085773>] spin_dump+0xa3/0xd0
 [  225.570000]  [<600859ba>] do_raw_spin_lock+0x18a/0x1a0
 [  225.570000]  [<6063e443>] _raw_spin_lock_irqsave+0x33/0x40
 [  225.570000]  [<6002b7a0>] ? do_IRQ+0x0/0x60
 [  225.570000]  [<6002b836>] sigio_handler+0x36/0x120
 [  225.570000]  [<60043db1>] sig_handler_common+0x71/0xe0
 [  225.570000]  [<6063e566>] ? _raw_spin_unlock_irqrestore+0x26/0x30
 [  225.570000]  [<603d2a2b>] ? debug_check_no_obj_freed+0x28b/0x2a0
 [  225.570000]  [<6011e8bc>] ? cache_free_debugcheck+0x17c/0x470
 [  225.570000]  [<6011f520>] ? kfree+0x0/0x170
 [  225.570000]  [<60398377>] ? blk_update_bidi_request+0x27/0x90
 [  225.570000]  [<6003c41e>] ? ubd_intr+0x4e/0x140
 [  225.570000]  [<6011f629>] ? kfree+0x109/0x170
 [  225.570000]  [<60040d10>] ? os_read_file+0x0/0x30
 [  225.570000]  [<6011f520>] ? kfree+0x0/0x170
 [  225.570000]  [<60040d10>] ? os_read_file+0x0/0x30
 [  225.570000]  [<6011f520>] ? kfree+0x0/0x170
 [  225.570000]  [<60398790>] ? blk_end_request+0x0/0x20
 [  225.570000]  [<60043f60>] ? get_signals+0x0/0x10
 [  225.570000]  [<60040d35>] ? os_read_file+0x25/0x30
 [  225.570000]  [<6003c435>] ? ubd_intr+0x65/0x140
 [  225.570000]  [<60043d40>] ? sig_handler_common+0x0/0xe0
 [  225.570000]  [<600438c0>] ? timer_real_alarm_handler+0x0/0x50
 [  225.570000]  [<60043d1c>] unblock_signals+0x8c/0xb0
 [  225.570000]  [<60052c2c>] __do_softirq+0x9c/0x2a0
 [  225.570000]  [<6008c63f>] ? handle_irq_event+0x5f/0x80
 [  225.570000]  [<6005313c>] irq_exit+0xac/0xb0
 [  225.570000]  [<6008bcd3>] ? generic_handle_irq+0x33/0x40
 [  225.570000]  [<6002b7e7>] do_IRQ+0x47/0x60
 [  225.570000]  [<6002b7a0>] ? do_IRQ+0x0/0x60
 [  225.570000]  [<6002b8da>] sigio_handler+0xda/0x120
 [  225.570000]  [<60043db1>] sig_handler_common+0x71/0xe0
 [  225.570000]  [<6004691a>] ? unmap+0x4a/0x50
 [  225.570000]  [<60074ff6>] ? __might_sleep+0x66/0xf0
 [  225.570000]  [<600dcc90>] ? get_page_from_freelist+0x0/0xa80
 [  225.570000]  [<600f2440>] ? next_zones_zonelist+0x0/0x40
 [  225.570000]  [<600dda67>] ? __alloc_pages_nodemask+0x177/0xb10
 [  225.570000]  [<600ffa96>] ? do_set_pte+0xa6/0xc0
 [  225.570000]  [<600d2781>] ? unlock_page+0x31/0xa0
 [  225.570000]  [<600d3d64>] ? filemap_map_pages+0x324/0x340
 [  225.570000]  [<60046ce2>] ? wait_stub_done+0x62/0x140
 [  225.570000]  [<600462d0>] ? run_syscall_stub+0xf0/0x350
 [  225.570000]  [<60043f70>] ? set_signals+0x0/0x50
 [  225.570000]  [<600468ca>] ? map+0x4a/0x50
 [  225.570000]  [<6002e724>] ? flush_tlb_page+0x134/0x240
 [  225.570000]  [<601011b0>] ? handle_mm_fault+0x0/0x1620
 [  225.570000]  [<6002ed35>] ? handle_page_fault+0x265/0x350
 [  225.570000]  [<60043d40>] ? sig_handler_common+0x0/0xe0
 [  225.570000]  [<600438c0>] ? timer_real_alarm_handler+0x0/0x50
 [  225.570000]  [<60043d1c>] unblock_signals+0x8c/0xb0
 [  225.570000]  [<6063e53c>] _raw_spin_unlock_irq+0x1c/0x20
 [  225.570000]  [<60074999>] finish_task_switch+0x59/0xe0
 [  225.570000]  [<6004a88b>] ? arch_switch_to+0x2b/0x30
 [  225.570000]  [<60639141>] __schedule+0x1e1/0x5b0
 [  225.570000]  [<60638f60>] ? __schedule+0x0/0x5b0
 [  225.570000]  [<60639544>] schedule+0x34/0x90
 [  225.570000]  [<6002f426>] ? segv_handler+0x46/0x90
 [  225.570000]  [<6002c374>] interrupt_end+0xa4/0xb0
 [  225.570000]  [<60047373>] userspace+0x253/0x4e0
 [  225.570000]  [<60030303>] ? do_op_one_page+0x153/0x240
 [  225.570000]  [<600429af>] ? save_registers+0x1f/0x40
 [  225.570000]  [<6004a806>] ? arch_prctl+0x1f6/0x220
 [  225.570000]  [<6002c055>] fork_handler+0x85/0x90
 [  225.570000]

with kind regards
thomas


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