linux-kernel - Re: [PATCH] tracing : Fix multiple issues in trace

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Message-ID: <aL3YlEZylChyTE5K@bombadil.infradead.org>
Date: Sun, 7 Sep 2025 12:10:12 -0700
From: Luis Chamberlain <mcgrof@...nel.org>
To: Fidal Palamparambil <rootuserhere@...il.com>
Cc: linux-modules@...r.kernel.org, petr.pavlu@...e.com, da.gomez@...nel.org,
	samitolvanen@...gle.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] tracing : Fix multiple issues in trace_printk module
 handling

On Sun, Sep 07, 2025 at 05:52:01PM +0400, Fidal Palamparambil wrote:
> From: Fidal palamparambil <rootuserhere@...il.com>
> 
> This commit addresses several bugs and potential issues in the
> trace_printk module format handling code:
> 
> 1. Memory leak fix: In hold_module_trace_bprintk_format(), ensure
>    proper cleanup when format string allocation fails by setting
>    tb_fmt to NULL after freeing it to prevent memory leaks.
> 
> 2. NULL pointer dereference prevention: Added comprehensive NULL checks
>    in t_show() function before dereferencing format pointers to prevent
>    kernel crashes.
> 
> 3. Input validation: Added NULL check in trace_is_tracepoint_string()
>    to prevent potential NULL pointer dereference when called with
>    invalid input.
> 
> 4. Type safety: Fixed type casting in t_show() to use proper
>    unsigned long casting for pointer arithmetic, ensuring correct
>    pointer handling across different architectures.
> 
> 5. Error handling: Fixed type mismatch in init_trace_printk_function_export()
>    by properly handling struct dentry pointer return from tracing_init_dentry()
>    and using IS_ERR_OR_NULL() for comprehensive error checking.
> 
> 6. Code robustness: Added additional pointer validation throughout
>    the code to handle potential edge cases and improve overall stability.
> 
> 7. Memory safety: Ensured consistent handling of format pointers
>    when memory allocation failures occur, preventing use-after-free
>    and other memory corruption issues.
> 
> These fixes improve the stability and reliability of the trace_printk
> infrastructure, particularly when dealing with module loading/unloading
> and format string management.
> 
> Reported-by : kernel test robot <lkp@...el.com>
> Closes : https://lore.kernel.org/oe-kbuild-all/202509071540.GTxwwstz-lkp@intel.com/
> Signed-off-by: Fidal palamparambil <rootuserhere@...il.com>

Stop, at this point after being told to stop, your intent is clear: to bug.

Go away. You're on my ignore list now.

  Luis