linux-kernel - [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON

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Date:   Tue, 20 Dec 2022 19:27:04 +0100
From:   "Uladzislau Rezki (Sony)" <urezki@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, LKML <linux-kernel@...r.kernel.org>,
        Baoquan He <bhe@...hat.com>,
        Christoph Hellwig <hch@...radead.org>,
        Matthew Wilcox <willy@...radead.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Uladzislau Rezki <urezki@...il.com>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>
Subject: [PATCH 2/2] mm: vmalloc: Replace BUG_ON() by WARN_ON_ONCE()

Currently a vm_unmap_ram() functions triggers a BUG() if an area
is not found. Replace it by the WARN_ON_ONCE() error message and
keep machine alive instead of stopping it.

The worst case is a memory leaking.

Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
 mm/vmalloc.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 0fc38c36e0df..e05a0dc79ac5 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2255,10 +2255,12 @@ void vm_unmap_ram(const void *mem, unsigned int count)
 	}
 
 	va = find_unlink_vmap_area(addr);
-	BUG_ON(!va);
-	debug_check_no_locks_freed((void *)va->va_start,
-				    (va->va_end - va->va_start));
-	free_unmap_vmap_area(va);
+
+	if (!WARN_ON_ONCE(!va)) {
+		debug_check_no_locks_freed((void *)va->va_start,
+			(va->va_end - va->va_start));
+		free_unmap_vmap_area(va);
+	}
 }
 EXPORT_SYMBOL(vm_unmap_ram);
 
-- 
2.30.2