The access_error() of vma already checked under per-VMA lock, if it
is a bad access, directly handle error, no need to retry with mmap_lock
again. In order to release the correct lock, pass the mm_struct into
bad_area_access_error(), if mm is NULL, release vma lock, or release
mmap_lock. Since the page faut is handled under per-VMA lock, count it
as a vma lock event with VMA_LOCK_SUCCESS.
Reviewed-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
arch/x86/mm/fault.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index a4cc20d0036d..67b18adc75dd 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -866,14 +866,17 @@ bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
static void
__bad_area(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, u32 pkey, int si_code)
+ unsigned long address, struct mm_struct *mm,
+ struct vm_area_struct *vma, u32 pkey, int si_code)
{
- struct mm_struct *mm = current->mm;
/*
* Something tried to access memory that isn't in our memory map..
* Fix it, but check if it's kernel or user first..
*/
- mmap_read_unlock(mm);
+ if (mm)
+ mmap_read_unlock(mm);
+ else
+ vma_end_read(vma);
__bad_area_nosemaphore(regs, error_code, address, pkey, si_code);
}
@@ -897,7 +900,8 @@ static inline bool bad_area_access_from_pkeys(unsigned long error_code,
static noinline void
bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, struct vm_area_struct *vma)
+ unsigned long address, struct mm_struct *mm,
+ struct vm_area_struct *vma)
{
/*
* This OSPKE check is not strictly necessary at runtime.
@@ -927,9 +931,9 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
*/
u32 pkey = vma_pkey(vma);
- __bad_area(regs, error_code, address, pkey, SEGV_PKUERR);
+ __bad_area(regs, error_code, address, mm, vma, pkey, SEGV_PKUERR);
} else {
- __bad_area(regs, error_code, address, 0, SEGV_ACCERR);
+ __bad_area(regs, error_code, address, mm, vma, 0, SEGV_ACCERR);
}
}
@@ -1357,8 +1361,9 @@ void do_user_addr_fault(struct pt_regs *regs,
goto lock_mmap;
if (unlikely(access_error(error_code, vma))) {
- vma_end_read(vma);
- goto lock_mmap;
+ bad_area_access_error(regs, error_code, address, NULL, vma);
+ count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+ return;
}
fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);
if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
@@ -1394,7 +1399,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* we can handle it..
*/
if (unlikely(access_error(error_code, vma))) {
- bad_area_access_error(regs, error_code, address, vma);
+ bad_area_access_error(regs, error_code, address, mm, vma);
return;
}
--
2.27.0
