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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-24 13:45:51 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 09:41:30 -0700
commit8d7071af890768438c14db6172cc8f9f4d04e184 (patch)
tree75db95708563f58bf8d1790ca77bde5b306f5dc0 /arch/parisc
parentf313c51d26aa87e69633c9b46efb37a930faca71 (diff)
mm: always expand the stack with the mmap write lock held
This finishes the job of always holding the mmap write lock when extending the user stack vma, and removes the 'write_locked' argument from the vm helper functions again. For some cases, we just avoid expanding the stack at all: drivers and page pinning really shouldn't be extending any stacks. Let's see if any strange users really wanted that. It's worth noting that architectures that weren't converted to the new lock_mm_and_find_vma() helper function are left using the legacy "expand_stack()" function, but it has been changed to drop the mmap_lock and take it for writing while expanding the vma. This makes it fairly straightforward to convert the remaining architectures. As a result of dropping and re-taking the lock, the calling conventions for this function have also changed, since the old vma may no longer be valid. So it will now return the new vma if successful, and NULL - and the lock dropped - if the area could not be extended. Tested-by: Vegard Nossum <vegard.nossum@oracle.com> Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> # ia64 Tested-by: Frank Scheiner <frank.scheiner@web.de> # ia64 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/parisc')
-rw-r--r--arch/parisc/mm/fault.c23
1 files changed, 11 insertions, 12 deletions
diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c
index 6941fdbf2517..6e894afa4249 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -288,15 +288,19 @@ void do_page_fault(struct pt_regs *regs, unsigned long code,
retry:
mmap_read_lock(mm);
vma = find_vma_prev(mm, address, &prev_vma);
- if (!vma || address < vma->vm_start)
- goto check_expansion;
+ if (!vma || address < vma->vm_start) {
+ if (!prev || !(prev->vm_flags & VM_GROWSUP))
+ goto bad_area;
+ vma = expand_stack(mm, address);
+ if (!vma)
+ goto bad_area_nosemaphore;
+ }
+
/*
* Ok, we have a good vm_area for this memory access. We still need to
* check the access permissions.
*/
-good_area:
-
if ((vma->vm_flags & acc_type) != acc_type)
goto bad_area;
@@ -347,17 +351,13 @@ good_area:
mmap_read_unlock(mm);
return;
-check_expansion:
- vma = prev_vma;
- if (vma && (expand_stack(vma, address) == 0))
- goto good_area;
-
/*
* Something tried to access memory that isn't in our memory map..
*/
bad_area:
mmap_read_unlock(mm);
+bad_area_nosemaphore:
if (user_mode(regs)) {
int signo, si_code;
@@ -449,7 +449,7 @@ handle_nadtlb_fault(struct pt_regs *regs)
{
unsigned long insn = regs->iir;
int breg, treg, xreg, val = 0;
- struct vm_area_struct *vma, *prev_vma;
+ struct vm_area_struct *vma;
struct task_struct *tsk;
struct mm_struct *mm;
unsigned long address;
@@ -485,7 +485,7 @@ handle_nadtlb_fault(struct pt_regs *regs)
/* Search for VMA */
address = regs->ior;
mmap_read_lock(mm);
- vma = find_vma_prev(mm, address, &prev_vma);
+ vma = vma_lookup(mm, address);
mmap_read_unlock(mm);
/*
@@ -494,7 +494,6 @@ handle_nadtlb_fault(struct pt_regs *regs)
*/
acc_type = (insn & 0x40) ? VM_WRITE : VM_READ;
if (vma
- && address >= vma->vm_start
&& (vma->vm_flags & acc_type) == acc_type)
val = 1;
}