Re: [PATCH] stats: fix io_u_plat out-of-bound accesses (round 2)

[Jens Axboe <axboe@kernel.dk>]

On 2011-08-16 01:23, Eric Gouriou wrote:
> Commit 833491908a1afd67 introduced the ability to report completion
> latency percentiles. It also caused a memory corruption when running
> with multiple threads due to out of bound accesses in show_run_stats().
> The major index of the io_u_plat two-dimensional array is meant
> to be DDIR_ value in {DDIR_READ, DDIR_WRITE} (i.e., {0, 1}). The
> code in show_run_stats() incorrectly wrote into the array using
> a major index with values {0, 1, 2}. Commit 0a0b49007cbce8d1 fixed
> the out of bound accesses by increasing the size of the major
> dimension of the io_u_plat array from 2 to 3.
> 
> This patch reverts the size change from 0a0b49007cbce8d1 in favor
> of avoiding the out-of-bound accesses in show_run_stats().

This makes more sense, I didn't look carefully enough at this, the 3rd
index is usually for trim.

> Jens, Zhu,
> 
> Yu-Ju is unlikely to be checking fio email traffic this week,
> hence my follow-up. The error was introduced while porting
> the patch between different versions of fio. The internal version
> was tested appropriately but not the upstream version.
> 
> Apologies for the trouble.

No worries, thanks for following up on this so quickly. My group replies
bounced on Yu-Ju's email.

-- 
Jens Axboe