Re: [PATCH 7/7] mincore: apply page table walker on do_mincore()
From: Sasha Levin
Date: Mon Jun 16 2014 - 11:24:36 EST
On 06/06/2014 06:58 PM, Naoya Horiguchi wrote:
> This patch makes do_mincore() use walk_page_vma(), which reduces many lines
> of code by using common page table walk code.
>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Hi Naoya,
This patch is causing a few issues on -next:
[ 367.679282] BUG: sleeping function called from invalid context at mm/mincore.c:37
[ 367.683618] in_atomic(): 1, irqs_disabled(): 0, pid: 10386, name: trinity-c13
[ 367.686236] 2 locks held by trinity-c13/10386:
[ 367.688006] #0: (&mm->mmap_sem){++++++}, at: SyS_mincore (mm/mincore.c:161 mm/mincore.c:245 mm/mincore.c:213)
[ 367.693232] #1: (&(ptlock_ptr(page))->rlock){+.+.-.}, at: __walk_page_range (mm/pagewalk.c:209 mm/pagewalk.c:262)
[ 367.698436] Preemption disabled __walk_page_range (mm/pagewalk.c:209 mm/pagewalk.c:262)
[ 367.700421]
[ 367.700803] CPU: 13 PID: 10386 Comm: trinity-c13 Not tainted 3.15.0-next-20140616-sasha-00025-g0fd1f7d #655
[ 367.703605] ffff88010bd08000 ffff88010bddbdd8 ffffffffb7514111 0000000000000002
[ 367.706819] 0000000000000000 ffff88010bddbe08 ffffffffb419ca64 ffff8801b209dc38
[ 367.710416] 00007fcc85400000 0000000000000000 ffff88010bddbef0 ffff88010bddbe38
[ 367.713101] Call Trace:
[ 367.714248] dump_stack (lib/dump_stack.c:52)
[ 367.716428] __might_sleep (kernel/sched/core.c:7080)
[ 367.723608] mincore_hugetlb (mm/mincore.c:37)
[ 367.725609] ? __walk_page_range (mm/pagewalk.c:209 mm/pagewalk.c:262)
[ 367.727712] __walk_page_range (include/linux/spinlock.h:343 mm/pagewalk.c:211 mm/pagewalk.c:262)
[ 367.729098] walk_page_vma (mm/pagewalk.c:376)
[ 367.731343] SyS_mincore (mm/mincore.c:178 mm/mincore.c:245 mm/mincore.c:213)
[ 367.733621] ? mincore_hugetlb (mm/mincore.c:144)
[ 367.735712] ? mincore_hole (mm/mincore.c:110)
[ 367.737022] ? mincore_page (mm/mincore.c:88)
[ 367.739416] ? copy_page_range (mm/mincore.c:24)
[ 367.741634] tracesys (arch/x86/kernel/entry_64.S:542)
And:
[ 391.118663] BUG: unable to handle kernel paging request at ffff880142aca000
[ 391.118663] IP: mincore_hole (mm/mincore.c:99 (discriminator 2))
[ 391.118663] PGD 3bbcd067 PUD 70574e067 PMD 705738067 PTE 8000000142aca060
[ 391.118663] Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 391.118663] Dumping ftrace buffer:
[ 391.118663] (ftrace buffer empty)
[ 391.118663] Modules linked in:
[ 391.118663] CPU: 4 PID: 9695 Comm: trinity-c566 Not tainted 3.15.0-next-20140616-sasha-00025-g0fd1f7d #655
[ 391.118663] task: ffff880044a5b000 ti: ffff880044adc000 task.ti: ffff880044adc000
[ 391.118663] RIP: mincore_hole (mm/mincore.c:99 (discriminator 2))
[ 391.118663] RSP: 0000:ffff880044adfd48 EFLAGS: 00010246
[ 391.118663] RAX: 0000000000000000 RBX: 0000000000007137 RCX: 0000005b107d3134
[ 391.118663] RDX: 0000000000000001 RSI: ffffffffb4b2dbe8 RDI: 0000000000000000
[ 391.118663] RBP: ffff880044adfd88 R08: 00000000000163fc R09: 0000000000000000
[ 391.118663] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000200
[ 391.118663] R13: ffff880142aca000 R14: ffff8800cadc0000 R15: 0000000000000001
[ 391.118663] FS: 00007fcc8afe0700(0000) GS:ffff880144e00000(0000) knlGS:0000000000000000
[ 391.118663] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 391.118663] CR2: ffff880142aca000 CR3: 0000000044a76000 CR4: 00000000000006a0
[ 391.118663] Stack:
[ 391.118663] ffff880044adfef0 ffff880142aca000 0000000000000000 00007fcc46a00000
[ 391.118663] 00007fcc4baee000 ffff880044adfef0 00007fcc46800000 ffff8800cad251a0
[ 391.118663] ffff880044adfe38 ffffffffb42d1c8d ffff880000000000 ffffffffb41a0038
[ 391.118663] Call Trace:
[ 391.118663] walk_pgd_range (mm/pagewalk.c:73 mm/pagewalk.c:141 mm/pagewalk.c:170)
[ 391.118663] ? preempt_count_sub (kernel/sched/core.c:2602)
[ 391.118663] __walk_page_range (mm/pagewalk.c:264)
[ 391.118663] ? SyS_mincore (mm/mincore.c:161 mm/mincore.c:245 mm/mincore.c:213)
[ 391.118663] walk_page_vma (mm/pagewalk.c:376)
[ 391.118663] SyS_mincore (mm/mincore.c:178 mm/mincore.c:245 mm/mincore.c:213)
[ 391.118663] ? mincore_hugetlb (mm/mincore.c:144)
[ 391.118663] ? mincore_hole (mm/mincore.c:110)
[ 391.118663] ? mincore_page (mm/mincore.c:88)
[ 391.118663] ? copy_page_range (mm/mincore.c:24)
[ 391.118663] tracesys (arch/x86/kernel/entry_64.S:542)
[ 391.118663] Code: 4d 85 e4 74 57 0f 1f 40 00 49 8b 86 a0 00 00 00 48 89 de 41 83 c7 01 4c 03 6d c8 48 83 c3 01 48 8b b8 f8 01 00 00 e8 ae fe ff ff <41> 88 45 00 4d 63 ef 4d 39 ec 77 d2 48 8b 4d c0 48 8b 49 50 48
All code
========
0: 4d 85 e4 test %r12,%r12
3: 74 57 je 0x5c
5: 0f 1f 40 00 nopl 0x0(%rax)
9: 49 8b 86 a0 00 00 00 mov 0xa0(%r14),%rax
10: 48 89 de mov %rbx,%rsi
13: 41 83 c7 01 add $0x1,%r15d
17: 4c 03 6d c8 add -0x38(%rbp),%r13
1b: 48 83 c3 01 add $0x1,%rbx
1f: 48 8b b8 f8 01 00 00 mov 0x1f8(%rax),%rdi
26: e8 ae fe ff ff callq 0xfffffffffffffed9
2b:* 41 88 45 00 mov %al,0x0(%r13) <-- trapping instruction
2f: 4d 63 ef movslq %r15d,%r13
32: 4d 39 ec cmp %r13,%r12
35: 77 d2 ja 0x9
37: 48 8b 4d c0 mov -0x40(%rbp),%rcx
3b: 48 8b 49 50 mov 0x50(%rcx),%rcx
3f: 48 rex.W
...
Code starting with the faulting instruction
===========================================
0: 41 88 45 00 mov %al,0x0(%r13)
4: 4d 63 ef movslq %r15d,%r13
7: 4d 39 ec cmp %r13,%r12
a: 77 d2 ja 0xffffffffffffffde
c: 48 8b 4d c0 mov -0x40(%rbp),%rcx
10: 48 8b 49 50 mov 0x50(%rcx),%rcx
14: 48 rex.W
...
[ 391.118663] RIP mincore_hole (mm/mincore.c:99 (discriminator 2))
[ 391.118663] RSP <ffff880044adfd48>
[ 391.118663] CR2: ffff880142aca000
Thanks,
Sasha
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