On (01/18/17 23:20), Dan Streetman wrote: > Change the BUG calls to WARN, and return error. > > There's no need to call BUG from this function, as it can safely return > the error. The only caller of this function is the zpool that zswap is > using, when zswap is trying to reduce the zpool size. While the error > does indicate a bug, as none of the WARN conditions should ever happen, > the zpool implementation can recover by trying to evict another page > or zswap will recover by sending the new page to the swap disk. > > This was reported in kernel bug 192571: > https://bugzilla.kernel.org/show_bug.cgi?id=192571 > > Reported-by: Gluzskiy Alexandr <sss123next@xxxxxxx> > Signed-off-by: Dan Streetman <ddstreet@xxxxxxxx> > --- > mm/zswap.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/mm/zswap.c b/mm/zswap.c > index 067a0d6..60c4e6f 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -787,7 +787,10 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) > return 0; > } > spin_unlock(&tree->lock); > - BUG_ON(offset != entry->offset); > + if (WARN_ON(offset != entry->offset)) { > + ret = -EINVAL; > + goto fail; > + } > > /* try to allocate swap cache page */ > switch (zswap_get_swap_cache_page(swpentry, &page)) { > @@ -813,8 +816,13 @@ static int zswap_writeback_entry(struct zpool *pool, unsigned long handle) > put_cpu_ptr(entry->pool->tfm); > kunmap_atomic(dst); > zpool_unmap_handle(entry->pool->zpool, entry->handle); > - BUG_ON(ret); > - BUG_ON(dlen != PAGE_SIZE); > + if (WARN(ret, "error decompressing page: %d\n", ret)) > + goto fail; > + if (WARN(dlen != PAGE_SIZE, > + "decompressed page only %x bytes\n", dlen)) { > + ret = -EINVAL; > + goto fail; > + } > > /* page is up to date */ > SetPageUptodate(page); + zswap_frontswap_load() I suppose. diff --git a/mm/zswap.c b/mm/zswap.c index 067a0d62f318..e2743687a202 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1023,13 +1023,13 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset, put_cpu_ptr(entry->pool->tfm); kunmap_atomic(dst); zpool_unmap_handle(entry->pool->zpool, entry->handle); - BUG_ON(ret); + WARN(ret, "error decompressing page: %d\n", ret); spin_lock(&tree->lock); zswap_entry_put(tree, entry); spin_unlock(&tree->lock); - return 0; + return ret; } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>