[andrea-aa:main 34/39] mm/userfaultfd.c:866:3-6: WARNING: Use BUG_ON instead of if condition followed by BUG.

[andrea-aa:main 34/39] mm/userfaultfd.c:866:3-6: WARNING: Use BUG_ON instead of if condition followed by BUG.

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
CC: linux-kernel(a)vger.kernel.org
TO: Andrea Arcangeli <aarcange@redhat.com>

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git main
head:   594ac4d4703392f80b124eebc2e2816ded6b92cf
commit: 9c170f87bcd588d29b1c0588f50d089041b0b1ef [34/39] userfaultfd: UFFDIO_REMAP uABI
:::::: branch date: 3 days ago
:::::: commit date: 3 days ago
config: riscv-randconfig-c003-20210920 (attached as .config)
compiler: riscv32-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>


cocci warnings: (new ones prefixed by >>)
>> mm/userfaultfd.c:866:3-6: WARNING: Use BUG_ON instead of if condition followed by BUG.
   Please make sure the condition has no side effects (see conditional BUG_ON definition in include/asm-generic/bug.h)
   mm/userfaultfd.c:918:3-6: WARNING: Use BUG_ON instead of if condition followed by BUG.
   Please make sure the condition has no side effects (see conditional BUG_ON definition in include/asm-generic/bug.h)

Please review and possibly fold the followup patch.

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org

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[PATCH] userfaultfd: fix bugon.cocci warnings

[kernel test robot]

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CC: kbuild-all(a)lists.01.org
CC: linux-kernel(a)vger.kernel.org
TO: Andrea Arcangeli <aarcange@redhat.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Linux Memory Management List <linux-mm@kvack.org>
CC: linux-kernel(a)vger.kernel.org

From: kernel test robot <lkp@intel.com>

mm/userfaultfd.c:866:3-6: WARNING: Use BUG_ON instead of if condition followed by BUG.
Please make sure the condition has no side effects (see conditional BUG_ON definition in include/asm-generic/bug.h)
mm/userfaultfd.c:918:3-6: WARNING: Use BUG_ON instead of if condition followed by BUG.
Please make sure the condition has no side effects (see conditional BUG_ON definition in include/asm-generic/bug.h)

 Use BUG_ON instead of a if condition followed by BUG.

Semantic patch information:
 This makes an effort to find cases where BUG() follows an if
 condition on an expression and replaces the if condition and BUG()
 with a BUG_ON having the conditional expression of the if statement
 as argument.

Generated by: scripts/coccinelle/misc/bugon.cocci

Fixes: 9c170f87bcd5 ("userfaultfd: UFFDIO_REMAP uABI")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: kernel test robot <lkp@intel.com>
---

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/andrea/aa.git main
head:   594ac4d4703392f80b124eebc2e2816ded6b92cf
commit: 9c170f87bcd588d29b1c0588f50d089041b0b1ef [34/39] userfaultfd: UFFDIO_REMAP uABI
:::::: branch date: 3 days ago
:::::: commit date: 3 days ago

Please take the patch only if it's a positive warning. Thanks!

 userfaultfd.c |    8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -861,9 +861,7 @@ static int remap_pages_pte(struct mm_str
 		WRITE_ONCE(src_page->index, linear_page_index(dst_vma,
 							      dst_addr));
 
-		if (!pte_same(ptep_clear_flush(src_vma, src_addr, src_pte),
-			      orig_src_pte))
-			BUG();
+		BUG_ON(!pte_same(ptep_clear_flush(src_vma, src_addr, src_pte), orig_src_pte));
 
 		orig_dst_pte = mk_pte(src_page, dst_vma->vm_page_prot);
 		orig_dst_pte = maybe_mkwrite(pte_mkdirty(orig_dst_pte),
@@ -913,9 +911,7 @@ static int remap_pages_pte(struct mm_str
 			return -EAGAIN;
 		}
 
-		if (pte_val(ptep_get_and_clear(src_mm, src_addr, src_pte)) !=
-		    pte_val(orig_src_pte))
-			BUG();
+		BUG_ON(pte_val(ptep_get_and_clear(src_mm, src_addr, src_pte)) != pte_val(orig_src_pte));
 		set_pte_at(dst_mm, dst_addr, dst_pte, orig_src_pte);
 
 		if (dst_mm != src_mm) {