[PATCH] Revert "mm/vunmap: add cond_resched() in vunmap_pmd_range"
From: Minchan Kim
Date: Thu Nov 05 2020 - 12:02:58 EST
This reverts commit e47110e90584a22e9980510b00d0dfad3a83354e.
While I was doing zram testing, I found sometimes decompression failed
since the compression buffer was corrupted. With investigation,
I found below commit calls cond_resched unconditionally so it could
make a problem in atomic context if the task is reschedule.
Revert the original commit for now.
[ 55.109012] BUG: sleeping function called from invalid context at mm/vmalloc.c:108^M
[ 55.110774] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 946, name: memhog^M
[ 55.111973] 3 locks held by memhog/946:^M
[ 55.112807] #0: ffff9d01d4b193e8 (&mm->mmap_lock#2){++++}-{4:4}, at: __mm_populate+0x103/0x160^M
[ 55.114151] #1: ffffffffa3d53de0 (fs_reclaim){+.+.}-{0:0}, at: __alloc_pages_slowpath.constprop.0+0xa98/0x1160^M
[ 55.115848] #2: ffff9d01d56b8110 (&zspage->lock){.+.+}-{3:3}, at: zs_map_object+0x8e/0x1f0^M
[ 55.118947] CPU: 0 PID: 946 Comm: memhog Not tainted 5.9.3-00011-gc5bfc0287345-dirty #316^M
[ 55.121265] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014^M
[ 55.122540] Call Trace:^M
[ 55.122974] dump_stack+0x8b/0xb8^M
[ 55.123588] ___might_sleep.cold+0xb6/0xc6^M
[ 55.124328] unmap_kernel_range_noflush+0x2eb/0x350^M
[ 55.125198] unmap_kernel_range+0x14/0x30^M
[ 55.125920] zs_unmap_object+0xd5/0xe0^M
[ 55.126604] zram_bvec_rw.isra.0+0x38c/0x8e0^M
[ 55.127462] zram_rw_page+0x90/0x101^M
[ 55.128199] bdev_write_page+0x92/0xe0^M
[ 55.128957] ? swap_slot_free_notify+0xb0/0xb0^M
[ 55.129841] __swap_writepage+0x94/0x4a0^M
[ 55.130636] ? do_raw_spin_unlock+0x4b/0xa0^M
[ 55.131462] ? _raw_spin_unlock+0x1f/0x30^M
[ 55.132261] ? page_swapcount+0x6c/0x90^M
[ 55.133038] pageout+0xe3/0x3a0^M
[ 55.133702] shrink_page_list+0xb94/0xd60^M
[ 55.134626] shrink_inactive_list+0x158/0x460^M
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Harish Sriram <harish@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
mm/vmalloc.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6ae491a8b210..a4f1d39ce710 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -102,8 +102,6 @@ static void vunmap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
if (pmd_none_or_clear_bad(pmd))
continue;
vunmap_pte_range(pmd, addr, next, mask);
-
- cond_resched();
} while (pmd++, addr = next, addr != end);
}
--
2.29.1.341.ge80a0c044ae-goog