On Wed, Jan 25, 2012 at 02:32:51PM -0800, Dan Magenheimer wrote: > I discovered this deadlock condition awhile ago working on RAMster > but it affects zcache as well. The list spinlock must be > locked prior to the page spinlock and released after. As > a result, the page copy must also be done while the locks are held. > > Applies to 3.2. Konrad, please push (via GregKH?)... > this is definitely a bug fix so need not be pushed during > a -rc0 window.
Looks good to me. Greg, could you apply the patch to your tree please? [Or would you rather I sent an GIT pull?] Thanks! > > Signed-off-by: Dan Magenheimer <[email protected]> > > diff --git a/drivers/staging/zcache/zcache-main.c > b/drivers/staging/zcache/zcache-main.c > index 56c1f9c..5b9f74e 100644 > --- a/drivers/staging/zcache/zcache-main.c > +++ b/drivers/staging/zcache/zcache-main.c > @@ -358,8 +358,8 @@ static struct zbud_hdr *zbud_create(uint16_t client_id, > uint16_t pool_id, > if (unlikely(zbpg == NULL)) > goto out; > /* ok, have a page, now compress the data before taking locks */ > - spin_lock(&zbpg->lock); > spin_lock(&zbud_budlists_spinlock); > + spin_lock(&zbpg->lock); > list_add_tail(&zbpg->bud_list, &zbud_unbuddied[nchunks].list); > zbud_unbuddied[nchunks].count++; > zh = &zbpg->buddy[0]; > @@ -389,12 +389,11 @@ init_zh: > zh->oid = *oid; > zh->pool_id = pool_id; > zh->client_id = client_id; > - /* can wait to copy the data until the list locks are dropped */ > - spin_unlock(&zbud_budlists_spinlock); > - > to = zbud_data(zh, size); > memcpy(to, cdata, size); > spin_unlock(&zbpg->lock); > + spin_unlock(&zbud_budlists_spinlock); > + > zbud_cumul_chunk_counts[nchunks]++; > atomic_inc(&zcache_zbud_curr_zpages); > zcache_zbud_cumul_zpages++; _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
