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From: Ralf Baechle <ralf@linux-mips.org>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: Paul Burton <paul.burton@imgtec.com>,
	linux-mips@linux-mips.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/10] binfmt_elf: load interpreter program headers earlier
Date: Thu, 13 Nov 2014 18:29:29 +0100	[thread overview]
Message-ID: <20141113172929.GA24983@linux-mips.org> (raw)
In-Reply-To: <20141113122011.GE23422@ulmo>

On Thu, Nov 13, 2014 at 01:20:20PM +0100, Thierry Reding wrote:

> kmemleak started complaining for me recently and the stacktrace (see
> below) points to this function:
> 
> 	unreferenced object 0xec0f77c0 (size 192):
> 	  comm "kworker/u8:0", pid 169, jiffies 4294939367 (age 86.360s)
> 	  hex dump (first 32 bytes):
> 	    01 00 00 70 1c ef 01 00 1c ef 01 00 1c ef 01 00  ...p............
> 	    a0 00 00 00 a0 00 00 00 04 00 00 00 04 00 00 00  ................
> 	  backtrace:
> 	    [<c00ec080>] __kmalloc+0x104/0x190
> 	    [<c01387d4>] load_elf_phdrs+0x60/0x8c
> 	    [<c0138cb4>] load_elf_binary+0x280/0x12d8
> 	    [<c00f8ef0>] search_binary_handler+0x80/0x1f0
> 	    [<c00fa370>] do_execveat_common+0x570/0x658
> 	    [<c00fa480>] do_execve+0x28/0x30
> 	    [<c0038eb4>] ____call_usermodehelper+0x144/0x19c
> 	    [<c000e638>] ret_from_fork+0x14/0x3c
> 	    [<ffffffff>] 0xffffffff
[...]
> I think what happens is that the interp_elf_phdata memory is freed only
> in the error cleanup path, but not when the function actually succeeds.
> 
> The attached patch plugs the leak for me.
> 
> Thierry

> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
> index f95da60e440e..8a9be83e88c2 100644
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -1029,6 +1029,7 @@ static int load_elf_binary(struct linux_binprm *bprm)
>  		}
>  	}
>  
> +	kfree(interp_elf_phdata);
>  	kfree(elf_phdata);
>  
>  	set_binfmt(&elf_format);

Folded in and testing now.

  Ralf

  reply	other threads:[~2014-11-13 17:29 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-11  7:30 [PATCH 00/10] MIPS O32 new FP ABI support Paul Burton
2014-09-11  7:30 ` [PATCH 01/10] binfmt_elf: hoist ELF program header loading to a function Paul Burton
2014-09-11  7:30 ` [PATCH 02/10] binfmt_elf: load interpreter program headers earlier Paul Burton
2014-11-13 12:20   ` Thierry Reding
2014-11-13 17:29     ` Ralf Baechle [this message]
2014-09-11  7:30 ` [PATCH 03/10] binfmt_elf: allow arch code to examine PT_LOPROC ... PT_HIPROC headers Paul Burton
2014-11-12 13:41   ` Thierry Reding
2014-11-13  0:16     ` Ralf Baechle
2014-11-13 12:25       ` Thierry Reding
2014-09-11  7:30 ` [PATCH 04/10] MIPS: define bits introduced for hybrid FPRs Paul Burton
2014-09-11  7:30 ` [PATCH 05/10] MIPS: detect presence of the FRE & UFR bits Paul Burton
2014-09-11  7:30 ` [PATCH 06/10] MIPS: ensure Config5.UFE is clear on boot Paul Burton
2014-09-11  7:30 ` [PATCH 07/10] MIPS: support for hybrid FPRs Paul Burton
2014-12-23 23:21   ` Aaro Koskinen
2014-12-23 23:31     ` James Hogan
2014-12-23 23:51       ` Aaro Koskinen
2014-09-11  7:30 ` [PATCH 08/10] MIPS: ELF: add definition for the .MIPS.abiflags section Paul Burton
2014-09-11  7:30 ` [PATCH 09/10] MIPS: ELF: set FP mode according to .MIPS.abiflags Paul Burton
2014-09-11  7:30 ` [PATCH 10/10] MIPS: Kconfig option to better exercise/debug hybrid FPRs Paul Burton

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