On 07.06.25 08:40, Tal Zussman wrote:
BUG_ON() is deprecated [1]. Convert all the BUG_ON()s and VM_BUG_ON()s
to use VM_WARN_ON_ONCE().
While at it, also convert the WARN_ON_ONCE()s in move_pages() to use
VM_WARN_ON_ONCE(), as the relevant conditions are already checked in
validate_range() in move_pages()'s caller.
[1] https://www.kernel.org/doc/html/v6.15/process/coding-style.html#use-warn-rather-than-bug
Signed-off-by: Tal Zussman <tz2294@xxxxxxxxxxxx>
---
[...]
if (ctx->features & UFFD_FEATURE_SIGBUS)
goto out;
@@ -411,12 +411,11 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
* to be sure not to return SIGBUS erroneously on
* nowait invocations.
*/
- BUG_ON(vmf->flags & FAULT_FLAG_RETRY_NOWAIT);
+ VM_WARN_ON_ONCE(vmf->flags & FAULT_FLAG_RETRY_NOWAIT);
#ifdef CONFIG_DEBUG_VM
if (printk_ratelimit()) {
- printk(KERN_WARNING
- "FAULT_FLAG_ALLOW_RETRY missing %x\n",
- vmf->flags);
+ pr_warn("FAULT_FLAG_ALLOW_RETRY missing %x\n",
+ vmf->flags);
You didn't cover that in the patch description.
I do wonder if we really still want the dump_stack() here and could
simplify to
pr_warn_ratelimited().
But I recall that the stack was helpful at least once for me (well, I
was able to reproduce and could have figured it out differently.).
[...]
err = uffd_move_lock(mm, dst_start, src_start, &dst_vma, &src_vma);
if (err)
@@ -1867,9 +1865,9 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start,
up_read(&ctx->map_changing_lock);
uffd_move_unlock(dst_vma, src_vma);
out:
- VM_WARN_ON(moved < 0);
- VM_WARN_ON(err > 0);
- VM_WARN_ON(!moved && !err);
+ VM_WARN_ON_ONCE(moved < 0);
+ VM_WARN_ON_ONCE(err > 0);
+ VM_WARN_ON_ONCE(!moved && !err);
return moved ? moved : err;
Here you convert VM_WARN_ON to VM_WARN_ON_ONCE without stating it in the
description (including the why).
@@ -1956,9 +1954,9 @@ int userfaultfd_register_range(struct userfaultfd_ctx *ctx,
for_each_vma_range(vmi, vma, end) {
cond_resched();
- BUG_ON(!vma_can_userfault(vma, vm_flags, wp_async));
- BUG_ON(vma->vm_userfaultfd_ctx.ctx &&
- vma->vm_userfaultfd_ctx.ctx != ctx);
+ VM_WARN_ON_ONCE(!vma_can_userfault(vma, vm_flags, wp_async));
+ VM_WARN_ON_ONCE(vma->vm_userfaultfd_ctx.ctx &&
+ vma->vm_userfaultfd_ctx.ctx != ctx);
WARN_ON(!(vma->vm_flags & VM_MAYWRITE));
Which raises the question, why this here should still be a WARN
--
Cheers,
David / dhildenb
