+ mm-skip-might_alloc-warnings-when-pf_memalloc-is-set.patch added to mm-new branch

+ mm-skip-might_alloc-warnings-when-pf_memalloc-is-set.patch added to mm-new branch

[Andrew Morton]

The patch titled
     Subject: mm: skip might_alloc() warnings when PF_MEMALLOC is set
has been added to the -mm mm-new branch.  Its filename is
     mm-skip-might_alloc-warnings-when-pf_memalloc-is-set.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-skip-might_alloc-warnings-when-pf_memalloc-is-set.patch

This patch will later appear in the mm-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
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fixup patches in mm-new.

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------------------------------------------------------
From: "Uladzislau Rezki (Sony)" <urezki@gmail.com>
Subject: mm: skip might_alloc() warnings when PF_MEMALLOC is set
Date: Tue, 7 Oct 2025 14:20:33 +0200

might_alloc() catches invalid blocking allocations in contexts where
sleeping is not allowed.

However when PF_MEMALLOC is set, the page allocator already skips reclaim
and other blocking paths.  In such cases, a blocking gfp_mask does not
actually lead to blocking, so triggering might_alloc() splats is
misleading.

Adjust might_alloc() to skip warnings when the current task has
PF_MEMALLOC set, matching the allocator's actual blocking behaviour.

Link: https://lkml.kernel.org/r/20251007122035.56347-9-urezki@gmail.com
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Marco Elver <elver@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/sched/mm.h |    3 +++
 1 file changed, 3 insertions(+)

--- a/include/linux/sched/mm.h~mm-skip-might_alloc-warnings-when-pf_memalloc-is-set
+++ a/include/linux/sched/mm.h
@@ -318,6 +318,9 @@ static inline void might_alloc(gfp_t gfp
 	fs_reclaim_acquire(gfp_mask);
 	fs_reclaim_release(gfp_mask);
 
+	if (current->flags & PF_MEMALLOC)
+		return;
+
 	might_sleep_if(gfpflags_allow_blocking(gfp_mask));
 }
 
_

Patches currently in -mm which might be from urezki@gmail.com are

lib-test_vmalloc-add-no_block_alloc_test-case.patch
lib-test_vmalloc-remove-xfail-condition-check.patch
mm-vmalloc-support-non-blocking-gfp-flags-in-alloc_vmap_area.patch
mm-vmalloc-defer-freeing-partly-initialized-vm_struct.patch
mm-vmalloc-handle-non-blocking-gfp-in-__vmalloc_area_node.patch
mm-kasan-support-non-blocking-gfp-in-kasan_populate_vmalloc.patch
kmsan-remove-hard-coded-gfp_kernel-flags.patch
mm-skip-might_alloc-warnings-when-pf_memalloc-is-set.patch
mm-vmalloc-update-__vmalloc_node_range-documentation.patch
mm-kvmalloc-add-non-blocking-support-for-vmalloc.patch