+ mm-fix-bug-splat-with-kvmalloc-gfp_atomic.patch added to mm-hotfixes-unstable branch

+ mm-fix-bug-splat-with-kvmalloc-gfp_atomic.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: fix BUG splat with kvmalloc + GFP_ATOMIC
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-fix-bug-splat-with-kvmalloc-gfp_atomic.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-fix-bug-splat-with-kvmalloc-gfp_atomic.patch

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

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------------------------------------------------------
From: Florian Westphal <fw@strlen.de>
Subject: mm: fix BUG splat with kvmalloc + GFP_ATOMIC
Date: Mon, 26 Sep 2022 17:16:50 +0200

Martin Zaharinov reports BUG with 5.19.10 kernel:
 kernel BUG at mm/vmalloc.c:2437!
 invalid opcode: 0000 [#1] SMP
 CPU: 28 PID: 0 Comm: swapper/28 Tainted: G        W  O      5.19.9 #1
 [..]
 RIP: 0010:__get_vm_area_node+0x120/0x130
  __vmalloc_node_range+0x96/0x1e0
  kvmalloc_node+0x92/0xb0
  bucket_table_alloc.isra.0+0x47/0x140
  rhashtable_try_insert+0x3a4/0x440
  rhashtable_insert_slow+0x1b/0x30
 [..]

bucket_table_alloc uses kvzalloc(GPF_ATOMIC).  If kmalloc fails, this now
falls through to vmalloc and hits code paths that assume GFP_KERNEL.

Link: https://lkml.kernel.org/r/20220926151650.15293-1-fw@strlen.de
Fixes: a421ef303008 ("mm: allow !GFP_KERNEL allocations for kvmalloc")
Signed-off-by: Florian Westphal <fw@strlen.de>
Suggested-by: Michal Hocko <mhocko@suse.com>
Link: https://lore.kernel.org/linux-mm/Yy3MS2uhSgjF47dy@pc636/T/#t
Acked-by: Michal Hocko <mhocko@suse.com>
Reported-by: Martin Zaharinov <micron10@gmail.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---


--- a/mm/util.c~mm-fix-bug-splat-with-kvmalloc-gfp_atomic
+++ a/mm/util.c
@@ -619,6 +619,10 @@ void *kvmalloc_node(size_t size, gfp_t f
 	if (ret || size <= PAGE_SIZE)
 		return ret;
 
+	/* non-sleeping allocations are not supported by vmalloc */
+	if (!gfpflags_allow_blocking(flags))
+		return NULL;
+
 	/* Don't even allow crazy sizes */
 	if (unlikely(size > INT_MAX)) {
 		WARN_ON_ONCE(!(flags & __GFP_NOWARN));
_

Patches currently in -mm which might be from fw@strlen.de are

mm-fix-bug-splat-with-kvmalloc-gfp_atomic.patch