lkml.org 
[lkml]   [2011]   [Jun]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH]mm: use correct address for pte_unmap_unlock in zap_pte_range
Boot an i386 kernel, I got:
[ 3.766613] WARNING: at /workshop/kernel/git/my/linux/arch/x86/mm/highmem_32.c:81 __kunmap_atomic+0x6f/0x113()
[ 3.766615] Hardware name: Studio XPS 8000
[ 3.766617] Modules linked in:
[ 3.766619] Pid: 214, comm: blkid Not tainted 3.0.0-rc3+ #529
[ 3.766621] Call Trace:
[ 3.766625] [<c1063803>] warn_slowpath_common+0x6a/0x7f
[ 3.766628] [<c104f494>] ? __kunmap_atomic+0x6f/0x113
[ 3.766631] [<c106382c>] warn_slowpath_null+0x14/0x18
[ 3.766633] [<c104f494>] __kunmap_atomic+0x6f/0x113
[ 3.766637] [<c10e6033>] zap_pte_range+0x291/0x2b4
[ 3.766641] [<c105a37d>] ? get_parent_ip+0xb/0x31
[ 3.766644] [<c10e6180>] unmap_page_range+0x12a/0x147
[ 3.766647] [<c10e6243>] unmap_vmas+0xa6/0xe2
[ 3.766650] [<c10e7c26>] exit_mmap+0x78/0xd3
[ 3.766654] [<c106207a>] mmput+0x39/0x99
[ 3.766657] [<c106582f>] exit_mm+0x101/0x109
[ 3.766660] [<c1066d83>] do_exit+0x1e6/0x312
[ 3.766664] [<c10fff66>] ? fput+0x18/0x1a
[ 3.766666] [<c1066f16>] do_group_exit+0x67/0x8a
[ 3.766669] [<c1066f51>] sys_exit_group+0x18/0x1c
[ 3.766673] [<c1620154>] syscall_call+0x7/0xb

the zap_pte_range does:
pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
do {
...
if (force_flush)
break;
...
} while (pte++, addr += PAGE_SIZE, addr != end);

pte_unmap_unlock(pte - 1, ptl);

the pte_unmap_unlock(pte - 1) only works if pte++ does once.

this is a regression introduced by d16dfc550f5326a4000f3(mm: mmu_gather
rework)

Signed-off-by: Shaohua Li <shaohua.li@intel.com>

diff --git a/mm/memory.c b/mm/memory.c
index 6953d39..f624945 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1112,11 +1112,11 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
int force_flush = 0;
int rss[NR_MM_COUNTERS];
spinlock_t *ptl;
- pte_t *pte;
+ pte_t *pte, *orig_pte;

again:
init_rss_vec(rss);
- pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ orig_pte = pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
arch_enter_lazy_mmu_mode();
do {
pte_t ptent = *pte;
@@ -1196,7 +1196,7 @@ again:

add_mm_rss_vec(mm, rss);
arch_leave_lazy_mmu_mode();
- pte_unmap_unlock(pte - 1, ptl);
+ pte_unmap_unlock(orig_pte, ptl);

/*
* mmu_gather ran out of room to batch pages, we break out of

\
 
 \ /
  Last update: 2011-06-15 12:31    [W:0.034 / U:18.548 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site