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[76.21.65.106]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-acec047944csm7272733a12.54.2025.02.02.23.29.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 02 Feb 2025 23:29:01 -0800 (PST) Date: Mon, 3 Feb 2025 01:28:59 -0600 From: Gautham Gujjula To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [ntfs3?] KMSAN: uninit-value in longest_match_std (2) Message-ID: References: <679a131a.050a0220.ac840.02d2.GAE@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <679a131a.050a0220.ac840.02d2.GAE@google.com> #syz test Hello, I've been unable to reproduce the error from this patch test by running ktest with my patch on top of 05dbaf8dd8bf ("Merge tag 'x86-urgent-2025-01-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip") and 2014c95afece ("Linux 6.14-rc1"). Since the error appears in the boot sequence before the actual reproducer executes, I don't believe this patch is the suspect. I'll resubmit the patch for testing, and take a deeper look if the problem reappears. Thanks, Gautham Gujjula diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c index fad68ff0b6ed..6fc4f960f4d9 100644 --- a/fs/ntfs3/file.c +++ b/fs/ntfs3/file.c @@ -1122,6 +1122,13 @@ static ssize_t ntfs_compress_write(struct kiocb *iocb, struct iov_iter *from) } goto out; } + } else if (to & (frame_size - 1)) { + for (ip = to >> PAGE_SHIFT, off = offset_in_page(to); + ip < pages_per_frame; + ip++, off = 0) { + zero_user_segment(pages[ip], off, PAGE_SIZE); + flush_dcache_page(pages[ip]); + } } }