Messages in this thread Patch in this message | | | Date | Wed, 15 Jun 2011 18:29:09 +0800 | From | Shaohua Li <> | Subject | [PATCH]mm: use correct address for pte_unmap_unlock in zap_pte_range |
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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
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