linux-kernel - [PATCH 5.19 030/101] mm: fix BUG splat with kvmalloc + GFP

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Message-Id: <20221003070725.223611597@linuxfoundation.org>
Date:   Mon,  3 Oct 2022 09:10:26 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Florian Westphal <fw@...len.de>,
        Michal Hocko <mhocko@...e.com>,
        Martin Zaharinov <micron10@...il.com>,
        "Uladzislau Rezki (Sony)" <urezki@...il.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH 5.19 030/101] mm: fix BUG splat with kvmalloc + GFP_ATOMIC

From: Florian Westphal <fw@...len.de>

commit 30c19366636f72515679aa10dad61a4d988d4c9a upstream.

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@...len.de>
Suggested-by: Michal Hocko <mhocko@...e.com>
Link: https://lore.kernel.org/linux-mm/Yy3MS2uhSgjF47dy@pc636/T/#t
Acked-by: Michal Hocko <mhocko@...e.com>
Reported-by: Martin Zaharinov <micron10@...il.com>
Cc: Uladzislau Rezki (Sony) <urezki@...il.com>
Cc: Vlastimil Babka <vbabka@...e.cz>
Cc: <stable@...r.kernel.org>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 mm/util.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/mm/util.c
+++ b/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));