From: Ville Syrjälä <[email protected]>
I got some khugepaged spew on a 32bit x86:
[ 217.490026] BUG: sleeping function called from invalid context at include/linux/mmu_notifier.h:346
[ 217.492826] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: khugepaged
[ 217.495589] INFO: lockdep is turned off.
[ 217.498371] CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-elk+ #206
[ 217.501233] Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203 07/08/2009
[ 217.501697] Call Trace:
[ 217.501697] dump_stack+0x66/0x8e
[ 217.501697] ___might_sleep.cold.96+0x95/0xa6
[ 217.501697] __might_sleep+0x2e/0x80
[ 217.501697] collapse_huge_page.isra.51+0x5ac/0x1360
[ 217.501697] ? __alloc_pages_nodemask+0xec/0xf80
[ 217.501697] ? __alloc_pages_nodemask+0x191/0xf80
[ 217.501697] ? trace_hardirqs_on+0x4a/0xf0
[ 217.501697] khugepaged+0x9a9/0x20f0
[ 217.501697] ? _raw_spin_unlock+0x21/0x30
[ 217.501697] ? trace_hardirqs_on+0x4a/0xf0
[ 217.501697] ? wait_woken+0xa0/0xa0
[ 217.501697] kthread+0xf5/0x110
[ 217.501697] ? collapse_pte_mapped_thp+0x3b0/0x3b0
[ 217.501697] ? kthread_create_worker_on_cpu+0x20/0x20
[ 217.501697] ret_from_fork+0x2e/0x38
Looks like it's due to CONFIG_HIGHPTE=y pte_offset_map()->kmap_atomic()
vs. mmu_notifier_invalidate_range_start(). Let's do the naive approach
and just reorder the two operations.
Cc: [email protected]
Cc: Andrew Morton <[email protected]>
Cc: "Kirill A. Shutemov" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: [email protected]
Signed-off-by: Ville Syrjälä <[email protected]>
---
mm/khugepaged.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 0a1b4b484ac5..f05d27b7183d 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1028,12 +1028,13 @@ static void collapse_huge_page(struct mm_struct *mm,
anon_vma_lock_write(vma->anon_vma);
- pte = pte_offset_map(pmd, address);
- pte_ptl = pte_lockptr(mm, pmd);
-
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
address, address + HPAGE_PMD_SIZE);
mmu_notifier_invalidate_range_start(&range);
+
+ pte = pte_offset_map(pmd, address);
+ pte_ptl = pte_lockptr(mm, pmd);
+
pmd_ptl = pmd_lock(mm, pmd); /* probably unnecessary */
/*
* After this gup_fast can't run anymore. This also removes
--
2.23.0
On Tue, 29 Oct 2019 23:25:13 +0200 Ville Syrjala <[email protected]> wrote:
> From: Ville Syrj?l? <[email protected]>
>
> I got some khugepaged spew on a 32bit x86:
>
> [ 217.490026] BUG: sleeping function called from invalid context at include/linux/mmu_notifier.h:346
> [ 217.492826] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: khugepaged
> [ 217.495589] INFO: lockdep is turned off.
> [ 217.498371] CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-elk+ #206
> [ 217.501233] Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203 07/08/2009
> [ 217.501697] Call Trace:
> [ 217.501697] dump_stack+0x66/0x8e
> [ 217.501697] ___might_sleep.cold.96+0x95/0xa6
> [ 217.501697] __might_sleep+0x2e/0x80
> [ 217.501697] collapse_huge_page.isra.51+0x5ac/0x1360
> [ 217.501697] ? __alloc_pages_nodemask+0xec/0xf80
> [ 217.501697] ? __alloc_pages_nodemask+0x191/0xf80
> [ 217.501697] ? trace_hardirqs_on+0x4a/0xf0
> [ 217.501697] khugepaged+0x9a9/0x20f0
> [ 217.501697] ? _raw_spin_unlock+0x21/0x30
> [ 217.501697] ? trace_hardirqs_on+0x4a/0xf0
> [ 217.501697] ? wait_woken+0xa0/0xa0
> [ 217.501697] kthread+0xf5/0x110
> [ 217.501697] ? collapse_pte_mapped_thp+0x3b0/0x3b0
> [ 217.501697] ? kthread_create_worker_on_cpu+0x20/0x20
> [ 217.501697] ret_from_fork+0x2e/0x38
>
> Looks like it's due to CONFIG_HIGHPTE=y pte_offset_map()->kmap_atomic()
> vs. mmu_notifier_invalidate_range_start(). Let's do the naive approach
> and just reorder the two operations.
Thanks.
I'll add
Fixes: 810e24e009cf71 ("mm/mmu_notifiers: annotate with might_sleep()")
Cc: <[email protected]>
although 810e24e009cf71 merely exposed the bug.
On Tue, Oct 29, 2019 at 11:25:13PM +0200, Ville Syrjala wrote:
> From: Ville Syrj?l? <[email protected]>
>
> I got some khugepaged spew on a 32bit x86:
>
> [ 217.490026] BUG: sleeping function called from invalid context at include/linux/mmu_notifier.h:346
> [ 217.492826] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 25, name: khugepaged
> [ 217.495589] INFO: lockdep is turned off.
> [ 217.498371] CPU: 1 PID: 25 Comm: khugepaged Not tainted 5.4.0-rc5-elk+ #206
> [ 217.501233] Hardware name: System manufacturer P5Q-EM/P5Q-EM, BIOS 2203 07/08/2009
> [ 217.501697] Call Trace:
> [ 217.501697] dump_stack+0x66/0x8e
> [ 217.501697] ___might_sleep.cold.96+0x95/0xa6
> [ 217.501697] __might_sleep+0x2e/0x80
> [ 217.501697] collapse_huge_page.isra.51+0x5ac/0x1360
> [ 217.501697] ? __alloc_pages_nodemask+0xec/0xf80
> [ 217.501697] ? __alloc_pages_nodemask+0x191/0xf80
> [ 217.501697] ? trace_hardirqs_on+0x4a/0xf0
> [ 217.501697] khugepaged+0x9a9/0x20f0
> [ 217.501697] ? _raw_spin_unlock+0x21/0x30
> [ 217.501697] ? trace_hardirqs_on+0x4a/0xf0
> [ 217.501697] ? wait_woken+0xa0/0xa0
> [ 217.501697] kthread+0xf5/0x110
> [ 217.501697] ? collapse_pte_mapped_thp+0x3b0/0x3b0
> [ 217.501697] ? kthread_create_worker_on_cpu+0x20/0x20
> [ 217.501697] ret_from_fork+0x2e/0x38
>
> Looks like it's due to CONFIG_HIGHPTE=y pte_offset_map()->kmap_atomic()
> vs. mmu_notifier_invalidate_range_start(). Let's do the naive approach
> and just reorder the two operations.
>
> Cc: [email protected]
> Cc: Andrew Morton <[email protected]>
> Cc: "Kirill A. Shutemov" <[email protected]>
> Cc: Thomas Gleixner <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: "H. Peter Anvin" <[email protected]>
> Cc: [email protected]
> Signed-off-by: Ville Syrj?l? <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
--
Kirill A. Shutemov