Re: [PATCH] nfsd: Move strlen declaration in nfsd4_encode_components_esc()

[Chuck Lever <chuck.lever@oracle.com>]

On 9/25/25 5:14 AM, Nathan Chancellor wrote:
> There is an error building nfs4xdr.c with CONFIG_SUNRPC_DEBUG_TRACE=y
> and CONFIG_FORTIFY_SOURCE=n due to the local variable strlen conflicting
> with the function strlen():
> 
>   In file included from include/linux/cpumask.h:11,
>                    from arch/x86/include/asm/paravirt.h:21,
>                    from arch/x86/include/asm/irqflags.h:102,
>                    from include/linux/irqflags.h:18,
>                    from include/linux/spinlock.h:59,
>                    from include/linux/mmzone.h:8,
>                    from include/linux/gfp.h:7,
>                    from include/linux/slab.h:16,
>                    from fs/nfsd/nfs4xdr.c:37:
>   fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_components_esc':
>   include/linux/kernel.h:321:46: error: called object 'strlen' is not a function or function pointer
>     321 |                 __trace_puts(_THIS_IP_, str, strlen(str));              \
>         |                                              ^~~~~~
>   include/linux/kernel.h:265:17: note: in expansion of macro 'trace_puts'
>     265 |                 trace_puts(fmt);                        \
>         |                 ^~~~~~~~~~
>   include/linux/sunrpc/debug.h:34:41: note: in expansion of macro 'trace_printk'
>      34 | #  define __sunrpc_printk(fmt, ...)     trace_printk(fmt, ##__VA_ARGS__)
>         |                                         ^~~~~~~~~~~~
>   include/linux/sunrpc/debug.h:42:17: note: in expansion of macro '__sunrpc_printk'
>      42 |                 __sunrpc_printk(fmt, ##__VA_ARGS__);                    \
>         |                 ^~~~~~~~~~~~~~~
>   include/linux/sunrpc/debug.h:25:9: note: in expansion of macro 'dfprintk'
>      25 |         dfprintk(FACILITY, fmt, ##__VA_ARGS__)
>         |         ^~~~~~~~
>   fs/nfsd/nfs4xdr.c:2646:9: note: in expansion of macro 'dprintk'
>    2646 |         dprintk("nfsd4_encode_components(%s)\n", components);
>         |         ^~~~~~~
>   fs/nfsd/nfs4xdr.c:2643:13: note: declared here
>    2643 |         int strlen, count=0;
>         |             ^~~~~~
> 
> Move the declaration of strlen into the while loop (as that is the only
> place where it is used), which is after the call to dprintk, to clear up
> the error.
> 
> Fixes: ec7d8e68ef0e ("sunrpc: add a Kconfig option to redirect dfprintk() output to trace buffer")
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> ---
> This solution may be too subtle but given that dprintk() seems to be on
> its way out, maybe it is fine. An alternative would be a rename such as
> str_len but there is some symmetry with pathlen so I opted for this one
> up front.
> ---
>  fs/nfsd/nfs4xdr.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index ea91bad4eee2..580bfa8011c7 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -2640,7 +2640,7 @@ static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep,
>  	__be32 *p;
>  	__be32 pathlen;
>  	int pathlen_offset;
> -	int strlen, count=0;
> +	int count=0;
>  	char *str, *end, *next;
>  
>  	dprintk("nfsd4_encode_components(%s)\n", components);
> @@ -2654,6 +2654,7 @@ static __be32 nfsd4_encode_components_esc(struct xdr_stream *xdr, char sep,
>  	end = str = components;
>  	while (*end) {
>  		bool found_esc = false;
> +		int strlen;
>  
>  		/* try to parse as esc_start, ..., esc_end, sep */
>  		if (*str == esc_enter) {
> 
> ---
> base-commit: 3fadfaec904dffab02ebf63dd9c2ae8fa15c6d32
> change-id: 20250925-nfsd-fix-trace-printk-strlen-error-2a24413eb186
> 
> Best regards,
> --  
> Nathan Chancellor <nathan@kernel.org>
> 

Would anyone be heartbroken if this patch removed the dprintk call site?

I think renaming the strlen variable to a name with a lower collision
risk would be sensible as well.


-- 
Chuck Lever