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[209.85.221.46]) by smtp.gmail.com with ESMTPSA id f5sm8230165ejj.45.2021.07.21.05.59.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 Jul 2021 05:59:22 -0700 (PDT) Received: by mail-wr1-f46.google.com with SMTP id f9so2081984wrq.11; Wed, 21 Jul 2021 05:59:22 -0700 (PDT) X-Received: by 2002:a5d:6caf:: with SMTP id a15mr42893600wra.313.1626872362525; Wed, 21 Jul 2021 05:59:22 -0700 (PDT) MIME-Version: 1.0 References: <162610726011.3408253.2771348573083023654.stgit@warthog.procyon.org.uk> <162610727640.3408253.8687445613469681311.stgit@warthog.procyon.org.uk> In-Reply-To: <162610727640.3408253.8687445613469681311.stgit@warthog.procyon.org.uk> From: Marc Dionne Date: Wed, 21 Jul 2021 09:59:11 -0300 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 2/4] afs: check function return To: David Howells Cc: linux-afs@lists.infradead.org, Tom Rix , linux-fsdevel@vger.kernel.org, Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Jul 12, 2021 at 1:28 PM David Howells wrote: > > From: Tom Rix > > Static analysis reports this problem > > write.c:773:29: warning: Assigned value is garbage or undefined > mapping->writeback_index = next; > ^ ~~~~ > The call to afs_writepages_region() can return without setting > next. So check the function return before using next. > > Changes: > ver #2: > - Need to fix the range_cyclic case also[1]. > > Fixes: e87b03f5830e ("afs: Prepare for use of THPs") > Signed-off-by: Tom Rix > Signed-off-by: David Howells > Link: https://lore.kernel.org/r/20210430155031.3287870-1-trix@redhat.com > Link: https://lore.kernel.org/r/162609464716.3133237.10354897554363093252.stgit@warthog.procyon.org.uk/ # v1 > Link: https://lore.kernel.org/r/CAB9dFdvHsLsw7CMnB+4cgciWDSqVjuij4mH3TaXnHQB8sz5rHw@mail.gmail.com/ [1] > --- > > fs/afs/write.c | 16 +++++++++++----- > 1 file changed, 11 insertions(+), 5 deletions(-) > > diff --git a/fs/afs/write.c b/fs/afs/write.c > index 3104b62c2082..1ed62e0ccfe5 100644 > --- a/fs/afs/write.c > +++ b/fs/afs/write.c > @@ -771,13 +771,19 @@ int afs_writepages(struct address_space *mapping, > if (wbc->range_cyclic) { > start = mapping->writeback_index * PAGE_SIZE; > ret = afs_writepages_region(mapping, wbc, start, LLONG_MAX, &next); > - if (start > 0 && wbc->nr_to_write > 0 && ret == 0) > - ret = afs_writepages_region(mapping, wbc, 0, start, > - &next); > - mapping->writeback_index = next / PAGE_SIZE; > + if (ret == 0) { > + mapping->writeback_index = next / PAGE_SIZE; > + if (start > 0 && wbc->nr_to_write > 0) { > + ret = afs_writepages_region(mapping, wbc, 0, > + start, &next); > + if (ret == 0) > + mapping->writeback_index = > + next / PAGE_SIZE; > + } > + } > } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { > ret = afs_writepages_region(mapping, wbc, 0, LLONG_MAX, &next); > - if (wbc->nr_to_write > 0) > + if (wbc->nr_to_write > 0 && ret == 0) > mapping->writeback_index = next; > } else { > ret = afs_writepages_region(mapping, wbc, > > Reviewed-by: Marc Dionne Marc