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Date:   Fri, 28 Apr 2023 18:11:54 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Jim Cromie <jim.cromie@gmail.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] kmemleak-test: drop __init to get better backtrace
Message-ID: <ZEv+Wi3eSD3fw0hR@arm.com>
References: <20230425222446.170486-1-jim.cromie@gmail.com>
 <20230425222446.170486-4-jim.cromie@gmail.com>
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On Tue, Apr 25, 2023 at 04:24:46PM -0600, Jim Cromie wrote:
> Drop the __init on kmemleak_test_init().  With it, the storage is
> reclaimed, but then the symbol isn't available for "%pS" rendering,
> and the backtrace gets a bare pointer where the actual leak happened.
> 
> unreferenced object 0xffff88800a2b0800 (size 1024):
>   comm "modprobe", pid 413, jiffies 4294953430
>   hex dump (first 32 bytes):
>     73 02 00 00 75 01 00 68 02 00 00 01 00 00 00 04  s...u..h........
>     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
>   backtrace (ck 603070071):
>     [<00000000fabad728>] kmalloc_trace+0x26/0x90
>     [<00000000ef738764>] 0xffffffffc02350a2
>     [<00000000004e5795>] do_one_initcall+0x43/0x210
>     [<00000000d768905e>] do_init_module+0x4a/0x210
>     [<0000000087135ab5>] __do_sys_finit_module+0x93/0xf0
>     [<000000004fcb1fa2>] do_syscall_64+0x34/0x80
>     [<00000000c73c8d9d>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
> 
> with __init gone, that trace entry renders like:
> 
>     [<00000000ef738764>] kmemleak_test_init+<offset>/<size>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>