On 03/25/2014 01:06 PM, Christoph Lameter wrote:
On Tue, 25 Mar 2014, Michal Hocko wrote:
You are right. The function even does VM_BUG_ON(!irqs_disabled())...
Unfortunatelly we do not seem to have an _irq alternative of the bit
spinlock.
Not sure what to do about it. Christoph?
Btw. it seems to go way back to 3.1 (1d07171c5e58e).
Well there is a preempt_enable() (bit_spin_lock) and a preempt_disable()
bit_spin_unlock() within a piece of code where irqs are disabled.
Is that a problem? Has been there for a long time.
So here's the full trace. There's obviously something wrong here since we
pagefault inside the section that was supposed to be running with irqs disabled
and I don't see another cause besides this.
The unreliable entries in the stack trace also somewhat suggest that the
fault is with the code I've pointed out.
[ 584.145271] BUG: sleeping function called from invalid context at arch/x86/mm/fault.c:1167
[ 584.148787] in_atomic(): 0, irqs_disabled(): 1, pid: 10089, name: trinity-c42
[ 584.150413] 1 lock held by trinity-c42/10089:
[ 584.151834] #0: (&mm->mmap_sem){++++++}, at: [<ffffffff8450aec3>] __do_page_fault+0x2e3/0x630
[ 584.151834] irq event stamp: 33318
[ 584.151834] hardirqs last enabled at (33317): [<ffffffff81282f15>] context_tracking_user_exit+0x1b5/0x260
[ 584.151834] hardirqs last disabled at (33318): [<ffffffff844b10d6>] __slab_alloc+0x41/0x637
[ 584.151834] softirqs last enabled at (33070): [<ffffffff81161a3e>] __do_softirq+0x3fe/0x560
[ 584.151834] softirqs last disabled at (33065): [<ffffffff81161f7c>] irq_exit+0x6c/0x170
[ 584.151834] CPU: 42 PID: 10089 Comm: trinity-c42 Tainted: G W 3.14.0-rc7-next-20140324-sasha-00015-g2fee858-dirty #271
[ 584.151834] ffff8800bc043000 ffff8800bc06f9c8 ffffffff844baf42 0000000000000001
[ 584.151834] 0000000000000000 ffff8800bc06f9f8 ffffffff81197ee1 ffffffff8450aec3
[ 584.151834] 0000000000000028 ffff8800bc06fb68 0000000000000a94 ffff8800bc06fb08
[ 584.151834] Call Trace:
[ 584.151834] [<ffffffff844baf42>] dump_stack+0x4f/0x7c
[ 584.151834] [<ffffffff81197ee1>] __might_sleep+0x221/0x240
[ 584.151834] [<ffffffff8450aec3>] ? __do_page_fault+0x2e3/0x630
[ 584.151834] [<ffffffff8450af0b>] __do_page_fault+0x32b/0x630
[ 584.151834] [<ffffffff8107aab5>] ? sched_clock+0x15/0x20
[ 584.151834] [<ffffffff811a2295>] ? sched_clock_local+0x25/0xa0
[ 584.151834] [<ffffffff811a2578>] ? sched_clock_cpu+0xa8/0xf0
[ 584.151834] [<ffffffff81282f07>] ? context_tracking_user_exit+0x1a7/0x260
[ 584.151834] [<ffffffff81b37063>] ? __this_cpu_preempt_check+0x13/0x20
[ 584.151834] [<ffffffff811c0664>] ? trace_hardirqs_off_caller+0x174/0x1a0
[ 584.151834] [<ffffffff8450b25e>] do_page_fault+0x4e/0xa0
[ 584.151834] [<ffffffff8450a775>] do_async_page_fault+0x35/0x100
[ 584.151834] [<ffffffff845073d8>] async_page_fault+0x28/0x30
[ 584.151834] [<ffffffff812e60e8>] ? deactivate_slab+0xc8/0x620
[ 584.151834] [<ffffffff812e5f70>] ? __cmpxchg_double_slab.isra.26+0x120/0x1d0
[ 584.151834] [<ffffffff812e611b>] ? deactivate_slab+0xfb/0x620
[ 584.151834] [<ffffffff812e60e8>] ? deactivate_slab+0xc8/0x620
[ 584.151834] [<ffffffff84506345>] ? _raw_spin_unlock+0x35/0x60
[ 584.151834] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.151834] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.151834] [<ffffffff81b37087>] ? debug_smp_processor_id+0x17/0x20
[ 584.151834] [<ffffffff812e3676>] ? set_track+0x96/0x180
[ 584.151834] [<ffffffff812e35ce>] ? init_object+0x6e/0x80
[ 584.151834] [<ffffffff844b15f9>] __slab_alloc+0x564/0x637
[ 584.151834] [<ffffffff810b9b24>] ? kvm_clock_read+0x24/0x40
[ 584.151834] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.151834] [<ffffffff8119b041>] ? get_parent_ip+0x11/0x50
[ 584.151834] [<ffffffff812e7ddc>] kmem_cache_alloc+0x12c/0x3b0
[ 584.151834] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.151834] [<ffffffff811a3288>] ? vtime_account_user+0x98/0xb0
[ 584.151834] [<ffffffff8132c5e1>] alloc_inode+0x41/0xa0
[ 584.151834] [<ffffffff8132e4fa>] new_inode_pseudo+0x1a/0x70
[ 584.151834] [<ffffffff8131837a>] create_pipe_files+0x2a/0x220
[ 584.151834] [<ffffffff811c28f4>] ? trace_hardirqs_on_caller+0x1f4/0x290
[ 584.151834] [<ffffffff813185b5>] __do_pipe_flags+0x45/0xe0
[ 584.151834] [<ffffffff81318770>] SyS_pipe+0x20/0xb0
[ 584.151834] [<ffffffff84510975>] ? tracesys+0x7e/0xe6
[ 584.151834] [<ffffffff845109d8>] tracesys+0xe1/0xe6
It was also followed by a straightforward NULL ptr deref in deactivate_slab():
[ 584.151834] BUG: unable to handle kernel NULL pointer dereference at 0000000000000a94
[ 584.151834] IP: [<ffffffff812e611b>] deactivate_slab+0xfb/0x620
[ 584.223982] PGD bc06c067 PUD bc06d067 PMD 0
[ 584.223982] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 584.223982] Dumping ftrace buffer:
[ 584.223982] (ftrace buffer empty)
[ 584.223982] Modules linked in:
[ 584.223982] CPU: 42 PID: 10089 Comm: trinity-c42 Tainted: G W 3.14.0-rc7-next-20140324-sasha-00015-g2fee858-dirty #271
[ 584.223982] task: ffff8800bc043000 ti: ffff8800bc06e000 task.ti: ffff8800bc06e000
[ 584.223982] RIP: 0010:[<ffffffff812e611b>] [<ffffffff812e611b>] deactivate_slab+0xfb/0x620
[ 584.223982] RSP: 0018:ffff8800bc06fc18 EFLAGS: 00010006
[ 584.223982] RAX: 0000000000000410 RBX: ffffea002bb04200 RCX: 0000000180180016
[ 584.223982] RDX: 0000000000000001 RSI: ffffffff812e60e8 RDI: ffffffff812e5f70
[ 584.223982] RBP: ffff8800bc06fd08 R08: ffffea0023ac6000 R09: 0000000000000080
[ 584.223982] R10: ffff880aec108408 R11: 0000000000000001 R12: ffffea0023ac6000
[ 584.223982] R13: ffff880a6c520000 R14: 0000000000000684 R15: 0000000000000684
[ 584.223982] FS: 00007feaa0845700(0000) GS:ffff880aecc00000(0000) knlGS:0000000000000000
[ 584.223982] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 584.223982] CR2: 0000000000000a94 CR3: 00000000bc06b000 CR4: 00000000000006a0
[ 584.223982] DR0: 0000000000698000 DR1: 0000000000698000 DR2: 0000000000000000
[ 584.223982] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000d9060a
[ 584.223982] Stack:
[ 584.223982] ffff8800bc043000 0000002a8450b958 ffff8800bc06e000 ffff8800bc06fc78
[ 584.223982] 00000000bc06fc58 ffffffff84506345 ffff88000000000f ffff880aec805600
[ 584.223982] ffffffff8132c5e1 0000000000000082 ffff880aec108418 0000000180180015
[ 584.223982] Call Trace:
[ 584.223982] [<ffffffff84506345>] ? _raw_spin_unlock+0x35/0x60
[ 584.223982] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.223982] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.223982] [<ffffffff81b37087>] ? debug_smp_processor_id+0x17/0x20
[ 584.223982] [<ffffffff812e3676>] ? set_track+0x96/0x180
[ 584.223982] [<ffffffff812e35ce>] ? init_object+0x6e/0x80
[ 584.223982] [<ffffffff844b15f9>] __slab_alloc+0x564/0x637
[ 584.223982] [<ffffffff810b9b24>] ? kvm_clock_read+0x24/0x40
[ 584.223982] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.223982] [<ffffffff8119b041>] ? get_parent_ip+0x11/0x50
[ 584.223982] [<ffffffff812e7ddc>] kmem_cache_alloc+0x12c/0x3b0
[ 584.223982] [<ffffffff8132c5e1>] ? alloc_inode+0x41/0xa0
[ 584.223982] [<ffffffff811a3288>] ? vtime_account_user+0x98/0xb0
[ 584.223982] [<ffffffff8132c5e1>] alloc_inode+0x41/0xa0
[ 584.223982] [<ffffffff8132e4fa>] new_inode_pseudo+0x1a/0x70
[ 584.223982] [<ffffffff8131837a>] create_pipe_files+0x2a/0x220
[ 584.223982] [<ffffffff811c28f4>] ? trace_hardirqs_on_caller+0x1f4/0x290
[ 584.223982] [<ffffffff813185b5>] __do_pipe_flags+0x45/0xe0
[ 584.223982] [<ffffffff81318770>] SyS_pipe+0x20/0xb0
[ 584.223982] [<ffffffff84510975>] ? tracesys+0x7e/0xe6
[ 584.223982] [<ffffffff845109d8>] tracesys+0xe1/0xe6
[ 584.223982] Code: 49 63 45 20 eb b2 66 2e 0f 1f 84 00 00 00 00 00 4d 85 f6 75 0b 4c 8b 63 10 45 31 ff eb 22 66 90 49 63 45 20 4d 89 f7 4c 8b 63 10 <49> 8b 14 06 48 85 d2 74 0c 49 89 d6 e9 7c ff ff ff 0f 1f 40 00
[ 584.223982] RIP [<ffffffff812e611b>] deactivate_slab+0xfb/0x620
[ 584.223982] RSP <ffff8800bc06fc18>
[ 584.223982] CR2: 0000000000000a94
Thanks,
Sasha
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