On Tue, 28 Apr 2009 14:43:37 +0200 (CEST) Bart <[email protected]> wrote: > > On Mon, 27 Apr 2009 13:36:46 -0700 (PDT) > > David Rientjes <[email protected]> wrote: > > > >> On Mon, 27 Apr 2009, Bart wrote: > >> > >>> After turning the suggested debuging options I've got tons of these when > >>> trying to stress the tape device like before: > >>> > >>> Apr 27 16:57:30 fs kernel: [ 96.446708] slab error in > >>> verify_redzone_free(): > >>> cache `size-128': memory outside object was overwritten > >>> Apr 27 16:57:30 fs kernel: [ 96.446713] Pid: 0, comm: swapper Not > >>> tainted > >>> 2.6.29.1-64 #2 > >>> Apr 27 16:57:30 fs kernel: [ 96.446715] Call Trace: > >>> Apr 27 16:57:30 fs kernel: [ 96.446717] <IRQ> [<ffffffff8029adc5>] > >>> __slab_error+0x1f/0x25 > >>> Apr 27 16:57:30 fs kernel: [ 96.446728] [<ffffffff8029b24b>] > >>> cache_free_debugcheck+0x108/0x1d6 > >>> Apr 27 16:57:30 fs kernel: [ 96.446731] [<ffffffff8029b473>] > >>> kfree+0x81/0xc2 > >>> Apr 27 16:57:30 fs kernel: [ 96.446735] [<ffffffff802bd311>] > >>> bio_free_map_data+0xc/0x1e > >> > >> This appears to be kfree(bmd->iovecs) in bio_free_map_data(). It looks > >> like the memcpy size in bio_set_map_data() overrides the kmalloc size; in > >> other words, for a redzone error, bio->bi_vcnt > nr_pages in > >> bio_copy_user_iov(). > > > > Can you try this? > > > > diff --git a/fs/bio.c b/fs/bio.c > > index 7bbc98f..6a09356 100644 > > --- a/fs/bio.c > > +++ b/fs/bio.c > > @@ -817,6 +817,9 @@ struct bio *bio_copy_user_iov(struct request_queue *q, > > len += iov[i].iov_len; > > } > > > > + if (offset) > > + nr_pages += 1; > > + > > bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask); > > if (!bmd) > > return ERR_PTR(-ENOMEM); > > > > There are no more errors in the dmesg after applying this patch to > 2.6.29.2. > > Without this patch I can reproduce this kind of errors on > 2.6.29.1, 2.6.29.2. > > I've not tested this patch with 2.6.29.1 and 2.6.30rc3-git3. > I will try to reproduce the error on 2.6.30rc3-git3 as soon as I compile > it.
Thanks for testing! And very sorry about the bug. I'm sure that you hit the same bug with 2.6.30-rc3-git. Jens, can you please apply this against 2.6.30-rc (and we need this for 2.6.29.x too)? I know that bio_copy_user_iov() is hacky. I'll try to clean up the mapping API later. = From: FUJITA Tomonori <[email protected]> Subject: [PATCH] bio: fix memcpy corruption in bio_copy_user_iov() st driver uses blk_rq_map_user() in order to just build a request out of page frames. In this case, map_data->offset is a non zero value and iov[0].iov_base is NULL. We need to increase nr_pages for that. Cc: [email protected] Signed-off-by: FUJITA Tomonori <[email protected]> --- fs/bio.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/fs/bio.c b/fs/bio.c index 7bbc98f..9871164 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -817,6 +817,9 @@ struct bio *bio_copy_user_iov(struct request_queue *q, len += iov[i].iov_len; } + if (offset) + nr_pages++; + bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask); if (!bmd) return ERR_PTR(-ENOMEM); -- 1.6.0.6 -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
