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Message-ID: <20221104095658.141222-2-lihuafei1@huawei.com>
Date: Fri, 4 Nov 2022 17:56:58 +0800
From: Li Huafei <lihuafei1@...wei.com>
To: <paul.walmsley@...ive.com>, <palmer@...belt.com>,
<aou@...s.berkeley.edu>, <lizhengyu3@...wei.com>,
<liaochang1@...wei.com>, <u.kleine-koenig@...gutronix.de>,
<rdunlap@...radead.org>
CC: <linux-riscv@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
<kexec@...ts.infradead.org>, <lihuafei1@...wei.com>
Subject: [PATCH 2/2] RISC-V: kexec: Fix memory leak of elf header buffer
This is reported by kmemleak detector:
unreferenced object 0xff2000000403d000 (size 4096):
comm "kexec", pid 146, jiffies 4294900633 (age 64.792s)
hex dump (first 32 bytes):
7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00 .ELF............
04 00 f3 00 01 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000566ca97c>] kmemleak_vmalloc+0x3c/0xbe
[<00000000979283d8>] __vmalloc_node_range+0x3ac/0x560
[<00000000b4b3712a>] __vmalloc_node+0x56/0x62
[<00000000854f75e2>] vzalloc+0x2c/0x34
[<00000000e9a00db9>] crash_prepare_elf64_headers+0x80/0x30c
[<0000000067e8bf48>] elf_kexec_load+0x3e8/0x4ec
[<0000000036548e09>] kexec_image_load_default+0x40/0x4c
[<0000000079fbe1b4>] sys_kexec_file_load+0x1c4/0x322
[<0000000040c62c03>] ret_from_syscall+0x0/0x2
In elf_kexec_load(), a buffer is allocated via vzalloc() to store elf
headers. While it's not freed back to system when kdump kernel is
reloaded or unloaded, or when image->elf_header is successfully set and
then fails to load kdump kernel for some reason. Fix it by freeing the
buffer in arch_kimage_file_post_load_cleanup().
Fixes: 8acea455fafa ("RISC-V: Support for kexec_file on panic")
Signed-off-by: Li Huafei <lihuafei1@...wei.com>
---
arch/riscv/kernel/elf_kexec.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/riscv/kernel/elf_kexec.c b/arch/riscv/kernel/elf_kexec.c
index ff30fcb43f47..5372b708fae2 100644
--- a/arch/riscv/kernel/elf_kexec.c
+++ b/arch/riscv/kernel/elf_kexec.c
@@ -26,6 +26,10 @@ int arch_kimage_file_post_load_cleanup(struct kimage *image)
kvfree(image->arch.fdt);
image->arch.fdt = NULL;
+ vfree(image->elf_headers);
+ image->elf_headers = NULL;
+ image->elf_headers_sz = 0;
+
return kexec_image_post_load_cleanup_default(image);
}
--
2.17.1
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