Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Date | Wed, 10 Dec 2014 16:37:43 -0800 | Subject | Re: [PATCH, 3.18] sleeping function called from invalid context |
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Adding Rik, who is probably the most recent person to have looked at the disaster fondly known as "FPU".
On Wed, Dec 10, 2014 at 4:25 PM, Daniel J Blueman <daniel@quora.org> wrote: > With 3.18, I was seeing a significant number of allocation warnings > from load_elf_binary call paths [1]. > > Allocating FPU state atomically [2] does prevent potentially sleeping > while atomic, but probably isn't the correct fix. Anyone familiar with > this area? > > -- [1] > > BUG: sleeping function called from invalid context at mm/slub.c:1240 > in_atomic(): 1, irqs_disabled(): 0, pid: 29016, name: dmesg > INFO: lockdep is turned off. > Preemption disabled at:[<ffffffff8114625f>] handle_mm_fault+0x5ff/0x8a0 > > CPU: 122 PID: 29016 Comm: dmesg Tainted: G W 3.18.0-test #6 > Hardware name: Supermicro AS -1042G-LTF/H8QGL, BIOS DS3.5a 11/13/2014 > ffffffff8203b81b ffff886fdf62f888 ffffffff81b942e8 0000000000000007 > 0000000000000000 ffff886fdf62f8b8 ffffffff8109ac4c 0000000000000000 > 0000000000000010 ffff8807df84bc00 00000000000000d0 ffff886fdf62f908 > Call Trace: > [<ffffffff81b942e8>] dump_stack+0x4f/0x7c > [<ffffffff8109ac4c>] __might_sleep+0x164/0x250 > [<ffffffff8116372b>] kmem_cache_alloc+0xeb/0x138 > [<ffffffff8100e0e1>] init_fpu+0x71/0xb0 > [<ffffffff81003966>] math_state_restore+0xce/0x208 > [<ffffffff8100437b>] do_device_not_available+0x2b/0x60 > [<ffffffff81ba70f5>] device_not_available+0x15/0x20 > [<ffffffff81487102>] ? copy_page+0x12/0x33
wtf? I don't see any fpu state being accessed in copy_page.
Can you disassemble "[<ffffffff81487102>] ? copy_page+0x12/0x33"?
--Andy
> [<ffffffff8109edb9>] ? get_parent_ip+0x11/0x58 > [<ffffffff8109ee55>] ? preempt_count_add+0x55/0xb0 > [<ffffffff811437a1>] ? do_cow_fault+0xe9/0x258 > [<ffffffff8114625f>] handle_mm_fault+0x5ff/0x8a0 > [<ffffffff81032218>] ? __do_page_fault+0xc8/0x498 > [<ffffffff811481b9>] ? vma_gap_callbacks_rotate+0x19/0x20 > [<ffffffff8103227d>] __do_page_fault+0x12d/0x498 > [<ffffffff810b682e>] ? up_write+0x1e/0x48 > [<ffffffff81148d18>] ? vma_link+0x80/0xc0 > [<ffffffff81149cb2>] ? vma_set_page_prot+0x3a/0x60 > [<ffffffff8114ae6e>] ? mmap_region+0x1be/0x5e0 > [<ffffffff8103262e>] do_page_fault+0x1e/0x70 > [<ffffffff81ba737f>] page_fault+0x1f/0x30 > [<ffffffff81487f3e>] ? __clear_user+0x2e/0x50 > [<ffffffff81487f22>] ? __clear_user+0x12/0x50 > [<ffffffff81487f8a>] clear_user+0x2a/0x30 > [<ffffffff811ca1e1>] padzero+0x21/0x30 > [<ffffffff811cc41f>] load_elf_binary+0x8cf/0xdd0 > [<ffffffff8117d18f>] search_binary_handler+0x7f/0x1f8 > [<ffffffff8117ec06>] do_execve_common.isra.34+0x616/0x790 > [<ffffffff8117eb62>] ? do_execve_common.isra.34+0x572/0x790 > [<ffffffff8117ed93>] do_execve+0x13/0x18 > [<ffffffff8117f070>] SyS_execve+0x20/0x30 > [<ffffffff81ba6159>] stub_execve+0x69/0xa0 > > -- [2] > > diff --git a/arch/x86/include/asm/fpu-internal.h > b/arch/x86/include/asm/fpu-internal.h > index e97622f..57029ad 100644 > --- a/arch/x86/include/asm/fpu-internal.h > +++ b/arch/x86/include/asm/fpu-internal.h > @@ -574,7 +574,7 @@ static inline int fpu_alloc(struct fpu *fpu) > { > if (fpu_allocated(fpu)) > return 0; > - fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL); > + fpu->state = kmem_cache_alloc(task_xstate_cachep, GFP_ATOMIC); > if (!fpu->state) > return -ENOMEM; > WARN_ON((unsigned long)fpu->state & 15); > -- > Daniel J Blueman
-- Andy Lutomirski AMA Capital Management, LLC
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