From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f69.google.com (mail-oo1-f69.google.com [209.85.161.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 494532C08DC for ; Fri, 17 Apr 2026 16:22:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776442930; cv=none; b=sk0yEITsV6CQRMvk+uoRMOSuSawQ6aInSKFIhJzFQWJBuLXLKX5q8CrBU1KAMGnyQvTstJE9gtOOXBLg/8eUt025V7z6dn0nvvgN67Mhkb0CRpcOTiVA/Gp0xWetfQcqulpBIAsIe5ABWiNjLzwCCYCQxOQxN5z6vdrLzC3NJn4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776442930; c=relaxed/simple; bh=4lPrpcToVuD+CER1ho/aNf/FgNU3utMEf2ocVM90p0A=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=mzaO4kOBplmZB+oOQcNgUZIi8XnqByTC7aoqhIcrbLQDyOWiZWYCFOCsqpim+d73VQ8Nitdt9Iv0zo1u06nLsSbU+/LWdpQgpvaaWo1FHcR6U7xWxnWSx+Iac3nDzEhOgL+q4ACJc1e8gUmDpNq8AYeRg1wB9m9BVdsc2L8kTHM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f69.google.com with SMTP id 006d021491bc7-66308f16ea1so1344534eaf.2 for ; Fri, 17 Apr 2026 09:22:09 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776442928; x=1777047728; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=XONuCj0368d1+eYHDok+Y4b/2UsVFvkjZUBNAuJWg2I=; b=nJOyUEe4QfQXx+E5IBwSCcS1LOe4bX+rPMPQBt4efdQ/I7ovtUOW9YXu+G20wmPMms GnMbOhY9u9yViymawRdKxBN/+Ifil7D/KuzkjHLq0zqoFJpH2A39TD7RKn6PENc//kwe Rn0QemGmHdZACpwdZv+aT3n+DnpTuZLoE1J8k+EfwBDFnP4a3J96vbPx8f6k75InO/3u 66U26r4+RCVOxPL4OtfL6DbK1L3t0J4SuHp+RM6RRRRV3gGeENpbzHwek+l3a2szZDNF zn1WioYBYQmAkNfI92Kf2cQiQMh29bi07Fei7LVwju5WASEFBoJBQdSRULA9mXGOI+XS lXGQ== X-Gm-Message-State: AOJu0YzcaelsZraLyku13Ln96EvhWunY/XWZ7Qfqt2Kg4utinGGJiuD8 C11qHV3tL0ifymwmRoh1HgMn7rCgQ8WdvnsLKKcVnWKuiQPLgL20hhbcrTwF1lUx/BOzaJWaD+c 3cL8kM476b0yuOWDseJT1FJSSATeO7Z4ftSz18EUZM9dEiXX6moH3fkKoDTY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:198c:b0:685:c62e:f8a8 with SMTP id 006d021491bc7-69462e311camr1881879eaf.17.1776442928307; Fri, 17 Apr 2026 09:22:08 -0700 (PDT) Date: Fri, 17 Apr 2026 09:22:08 -0700 In-Reply-To: <68da879e.050a0220.1696c6.0016.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e25e30.a00a0220.1cdc.001c.GAE@google.com> Subject: Forwarded: Re: [syzbot] KASAN: slab-use-after-free Read in lbmIODone From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: [syzbot] KASAN: slab-use-after-free Read in lbmIODone Author: tristmd@gmail.com #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >>From 9fd2228641cd56d9e735211ce0d2decfd03aaaa9 Mon Sep 17 00:00:00 2001 From: Tristan Madani Date: Fri, 17 Apr 2026 16:15:16 +0000 Subject: [PATCH] jfs: fix use-after-free in lbmIODone by waiting for in-flight I/O lbmLogShutdown() frees all log buffer heads without waiting for outstanding block I/O completions. When a write bio submitted via lbmStartIO() completes after the buffers are freed, lbmIODone() dereferences the freed struct lbuf via bio->bi_private. Add an atomic io_count and wait_queue_head_t to struct jfs_log. Increment before submit_bio(), decrement after processing in lbmIODone(), and wait in lbmLogShutdown() for io_count == 0 before freeing. Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c Signed-off-by: Tristan Madani --- fs/jfs/jfs_logmgr.c | 15 ++++++++++++++- fs/jfs/jfs_logmgr.h | 3 +++ 2 files changed, 17 insertions(+), 1 deletion(-) diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c index 306165e..e309e1b 100644 --- a/fs/jfs/jfs_logmgr.c +++ b/fs/jfs/jfs_logmgr.c @@ -1805,6 +1805,9 @@ static int lbmLogInit(struct jfs_log * log) */ init_waitqueue_head(&log->free_wait); + atomic_set(&log->io_count, 0); + init_waitqueue_head(&log->io_wait); + log->lbuf_free = NULL; for (i = 0; i < LOGPAGES;) { @@ -1855,6 +1858,8 @@ static void lbmLogShutdown(struct jfs_log * log) jfs_info("lbmLogShutdown: log:0x%p", log); + wait_event(log->io_wait, atomic_read(&log->io_count) == 0); + lbuf = log->lbuf_free; while (lbuf) { struct lbuf *next = lbuf->l_freelist; @@ -2128,6 +2133,7 @@ static void lbmStartIO(struct lbuf * bp) bio->bi_iter.bi_size = 0; lbmIODone(bio); } else { + atomic_inc(&log->io_count); submit_bio(bio); INCREMENT(lmStat.submitted); } @@ -2170,12 +2176,16 @@ static void lbmIODone(struct bio *bio) struct lbuf *nextbp, *tail; struct jfs_log *log; unsigned long flags; + int is_write; /* * get back jfs buffer bound to the i/o buffer */ jfs_info("lbmIODone: bp:0x%p flag:0x%x", bp, bp->l_flag); + log = bp->l_log; + is_write = !(bp->l_flag & lbmREAD); + LCACHE_LOCK(flags); /* disable+lock */ if (bio->bi_status) { @@ -2214,7 +2224,6 @@ static void lbmIODone(struct bio *bio) INCREMENT(lmStat.pagedone); /* update committed lsn */ - log = bp->l_log; log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor; if (bp->l_flag & lbmDIRECT) { @@ -2299,6 +2308,10 @@ static void lbmIODone(struct bio *bio) out: bp->l_flag |= lbmDONE; LCACHE_UNLOCK(flags); + + if (is_write && !log->no_integrity) + if (atomic_dec_and_test(&log->io_count)) + wake_up(&log->io_wait); } int jfsIOWait(void *arg) diff --git a/fs/jfs/jfs_logmgr.h b/fs/jfs/jfs_logmgr.h index 09e0ef6..6fa7d9f 100644 --- a/fs/jfs/jfs_logmgr.h +++ b/fs/jfs/jfs_logmgr.h @@ -400,6 +400,9 @@ struct jfs_log { uuid_t uuid; /* 16: 128-bit uuid of log device */ int no_integrity; /* 3: flag to disable journaling to disk */ + + atomic_t io_count; /* outstanding I/O count */ + wait_queue_head_t io_wait; /* wait for all I/O to complete */ }; /* -- 2.47.3