Re: reiserfs: inconsistent format in __RASSERT

[Jeff Mahoney]

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On 3/16/15 8:55 AM, Nicolas Iooss wrote:
> Hello,
> 
> When adding a __printf attribute to reiserfs_panic, gcc reported
> an inconsistent format for __RASSERT.  This macro is currently
> defined in fs/reiserfs/reiserfs.h as:
> 
> reiserfs_panic(NULL, "assertion failure", "(" #cond ") at " \ 
> __FILE__ ":%i:%s: " format "\n",                        \ 
> in_interrupt() ? -1 : task_pid_nr(current),             \ __LINE__,
> __func__ , ##args);
> 
> In the format string, the first parameter is a line number, but in
> the arguments there is a PID before.  Before c3a9c2109f84
> ("reiserfs: rework reiserfs_panic") [1], the format string began
> with "reiserfs[%i]" [2], which explains the PID in the arguments.
> 
> I see three possibilities:
> 
> * I missed something in my analysis and in fact the PID argument
> is processed by reiserfs_panic (don't know where), or * the PID
> argument is not used and should be removed, or

This, please. reiserfs_panic calls BUG(), which will contain the PID.

> * the PID is useful and "[%i]" should be added somewhere in the
> format string.
> 
> Which one would you prefer?
> 
> Also, I found this when building the kernel with "allmodconfig" on 
> x86_64.  With "defconfig" gcc does not report this error, but I
> guess it is because without CONFIG_REISERFS_CHECK, __RASSERT is
> never used.

Yeah. If reiserfs was more actively maintained, what is currently
protected by CONFIG_REISERFS_CHECK would be handled a bit better.
There are ton of fsfuzzer bugs that would be caught by it and should
be handled using reiserfs_error. Unfortunately, it also enables some
heavy checks that make the file system very slow.

Thanks for looking into this. It looks like it's been broken for a
while. I suppose the only saving grace is that it would crash in a
path that crashes on purpose a few lines later.

- -Jeff

- -- 
Jeff Mahoney
SUSE Labs
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