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Message-Id: <20190124115648.9433-2-urezki@gmail.com>
Date: Thu, 24 Jan 2019 12:56:47 +0100
From: "Uladzislau Rezki (Sony)" <urezki@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Michal Hocko <mhocko@...e.com>,
Matthew Wilcox <willy@...radead.org>, linux-mm@...ck.org
Cc: LKML <linux-kernel@...r.kernel.org>,
Thomas Garnier <thgarnie@...gle.com>,
Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
Steven Rostedt <rostedt@...dmis.org>,
Joel Fernandes <joelaf@...gle.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...e.hu>, Tejun Heo <tj@...nel.org>,
"Uladzislau Rezki (Sony)" <urezki@...il.com>
Subject: [PATCH v1 1/2] mm/vmalloc: fix kernel BUG at mm/vmalloc.c:512!
One of the vmalloc stress test case triggers the kernel BUG():
<snip>
[60.562151] ------------[ cut here ]------------
[60.562154] kernel BUG at mm/vmalloc.c:512!
[60.562206] invalid opcode: 0000 [#1] PREEMPT SMP PTI
[60.562247] CPU: 0 PID: 430 Comm: vmalloc_test/0 Not tainted 4.20.0+ #161
[60.562293] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
[60.562351] RIP: 0010:alloc_vmap_area+0x36f/0x390
<snip>
it can happen due to big align request resulting in overflowing
of calculated address, i.e. it becomes 0 after ALIGN()'s fixup.
Fix it by checking if calculated address is within vstart/vend
range.
Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
---
mm/vmalloc.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 1c512fff8a56..fb4fb5fcee74 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -498,7 +498,11 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
}
found:
- if (addr + size > vend)
+ /*
+ * Check also calculated address against the vstart,
+ * because it can be 0 because of big align request.
+ */
+ if (addr + size > vend || addr < vstart)
goto overflow;
va->va_start = addr;
--
2.11.0
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