On 10/04/2024 10:07, Kefeng Wang wrote:
On 2024/4/10 15:32, Alexandre Ghiti wrote:
Hi Kefeng,
On 03/04/2024 10:38, Kefeng Wang wrote:
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. 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/riscv/mm/fault.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index 3ba1d4dde5dd..b3fcf7d67efb 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -292,7 +292,10 @@ void handle_page_fault(struct pt_regs *regs)
if (unlikely(access_error(cause, vma))) {
vma_end_read(vma);
- goto lock_mmap;
+ count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+ tsk->thread.bad_cause = SEGV_ACCERR;
I think we should use the cause variable here instead of SEGV_ACCERR,
as bad_cause is a riscv internal status which describes the real
fault that happened.
Oh, I see, it is exception causes on riscv, so it should be
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index b3fcf7d67efb..5224f3733802 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -293,8 +293,8 @@ void handle_page_fault(struct pt_regs *regs)
if (unlikely(access_error(cause, vma))) {
vma_end_read(vma);
count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
- tsk->thread.bad_cause = SEGV_ACCERR;
- bad_area_nosemaphore(regs, code, addr);
+ tsk->thread.bad_cause = cause;
+ bad_area_nosemaphore(regs, SEGV_ACCERR, addr);
return;
}
Hi Alex, could you help to check it?
Hi Andrew, please help to squash it after Alex ack it.
Thanks both.
So I have just tested Kefeng's fixup on my usual CI and with a simple
program that triggers such bad access, everything went fine so with the
fixup applied:
Reviewed-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Tested-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Thanks,
Alex
Thanks,
Alex
+ bad_area_nosemaphore(regs, code, addr);
+ return;
}
fault = handle_mm_fault(vma, addr, flags |
FAULT_FLAG_VMA_LOCK, regs);
