From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f79.google.com (mail-ot1-f79.google.com [209.85.210.79]) (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 89A8213C9C4 for ; Mon, 20 Apr 2026 04:08:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.79 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776658117; cv=none; b=ZOP9QpJ1XPw472bi+ENwsqwbX66QitMhdaK+7emqrwhzNdiJldEQaZWCesQDlj/u4BXqd+BNVEyHoxHqwG5FVobyGn3tq3y/Ssoi4L6ETojk/U2j8TPKKRkjOEFqaLyYikOmAWBxfMZQ3HRhZRmQ+nQ8ul3zdhhMgTFETbXJuVs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776658117; c=relaxed/simple; bh=x7avjVMJoexGIsNr/vNRI5jUWIVdtEXK8MeP6L20z5Y=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=UArcqaxkvigeGIdmee1seOCPu/dkGoYrvlUhyRNhF+1WvrdaVIT+FkROWdCe2gPvE4aWyC3Xn8gQv+ea4rudRkoZBUqi2v2oihlAMGiwLK5AfsjD5FT3kQOx1GRAYKBBWR1xA5p1X3UcQNTA6MyTW3sS7IsiIzSME+duchTFSB8= 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=209.85.210.79 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-ot1-f79.google.com with SMTP id 46e09a7af769-7dbb4a976adso3021181a34.2 for ; Sun, 19 Apr 2026 21:08:35 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776658114; x=1777262914; 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=qWhDiJdqGFcdbqsDHy9p5PvmMcoDTaRA2oSoFo11eys=; b=gF1e3XbXUpzEb3CBDUZyt4sQH+BJfT+SPsPrrcmjt4Q4/dJQQUIkPMTFQ1EOP3golN ZJLGw5IPcXpcKH89/AAAwy3zxYt4N1jcI0n43wunJsrds0U3f3O41O5Y/10QbivqAzZy gkq7UNiAteXFA/lYSHsYBMC/8W8VbWX4Tq63kmTaXmObPfEQkBOOJI6KywJbKaB0TR4L mMvePfwN4r+D4hhoOhhRYrD4Xd4yJr9U72jZy6tHRw93ciRlVZZ2lD04iMjZGlvKoTLT qNZVpBcDD2WLt5qpH/JCK5CY9okRsnMcS4Pz29yE6lv+NYgYYSBtZ7u2Q6ivMCAcIuyw 8mqw== X-Gm-Message-State: AOJu0Yy61Oyi/Dy8pIw+Jxu/3Un3zACELEg8o5SMHJsFDvzZATlytfK7 X45nJnq3gnzul/JPkjU4ZhTNlBF2kuVDqc8ZLEG/VFaL96lhX/vYENMe0PYRK7Q1fbCvyFaN4PL yM9cdTeKlc7VpJwmb/IL574Nja1QBLAxZ86VkGHMesWU50iBQ8NyBWg83LjedOA== Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:161f:b0:68c:78d2:e7e6 with SMTP id 006d021491bc7-69462f44dbemr6028470eaf.56.1776658114501; Sun, 19 Apr 2026 21:08:34 -0700 (PDT) Date: Sun, 19 Apr 2026 21:08:34 -0700 In-Reply-To: <69ca48ca.050a0220.183828.001a.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <69e5a6c2.050a0220.24bfd3.0021.GAE@google.com> Subject: Forwarded: Re: [syzbot] [mm?] KASAN: use-after-free Read in copy_folio_from_iter_atomic (2) 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] [mm?] KASAN: use-after-free Read in copy_folio_from_iter_atomic (2) Author: suresh.k.chandrappa@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master >From 56a838ee6e3c6834a7e7705472144b1c84a4d8f8 Mon Sep 17 00:00:00 2001 From: Suresh K C Date: Sat, 18 Apr 2026 10:14:20 +0530 Subject: [PATCH] jfs: fix use-after-free in lbmIODone Add an atomic io_inflight counter and a wait queue (io_waitq) to struct jfs_log to track in-flight I/O operations. This ensures that lbmLogShutdown() waits for all pending log I/O to complete before freeing log buffers, preventing a use-after-free race condition where the loop device workqueue could still be reading from log buffer pages that have already been freed. The io_inflight counter is incremented in lbmRead() and lbmStartIO() before submitting bios, and decremented in lbmIODone() after I/O completion processing is finished. Reported-by: syzbot+6cc93ec9a4035badb85f@syzkaller.appspotmail.com Signed-off-by: Suresh K C --- fs/jfs/jfs_logmgr.c | 12 +++++++++++- fs/jfs/jfs_logmgr.h | 3 +++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c index 306165e61438..e8ae90be089b 100644 --- a/fs/jfs/jfs_logmgr.c +++ b/fs/jfs/jfs_logmgr.c @@ -1804,6 +1804,7 @@ static int lbmLogInit(struct jfs_log * log) * avoid deadlock here. */ init_waitqueue_head(&log->free_wait); + init_waitqueue_head(&log->io_waitq); log->lbuf_free = NULL; @@ -1855,6 +1856,8 @@ static void lbmLogShutdown(struct jfs_log * log) jfs_info("lbmLogShutdown: log:0x%p", log); + wait_event(log->io_waitq, !atomic_read(&log->io_inflight)); + lbuf = log->lbuf_free; while (lbuf) { struct lbuf *next = lbuf->l_freelist; @@ -1976,6 +1979,8 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp) bio->bi_end_io = lbmIODone; bio->bi_private = bp; + + atomic_inc(&log->io_inflight); /*check if journaling to disk has been disabled*/ if (log->no_integrity) { bio->bi_iter.bi_size = 0; @@ -2123,6 +2128,7 @@ static void lbmStartIO(struct lbuf * bp) bio->bi_end_io = lbmIODone; bio->bi_private = bp; + atomic_inc(&log->io_inflight); /* check if journaling to disk has been disabled */ if (log->no_integrity) { bio->bi_iter.bi_size = 0; @@ -2186,6 +2192,8 @@ static void lbmIODone(struct bio *bio) bio_put(bio); + log = bp->l_log; + /* * pagein completion */ @@ -2214,7 +2222,6 @@ 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 +2306,9 @@ static void lbmIODone(struct bio *bio) out: bp->l_flag |= lbmDONE; LCACHE_UNLOCK(flags); + + if (atomic_dec_and_test(&log->io_inflight)) + wake_up(&log->io_waitq); } int jfsIOWait(void *arg) diff --git a/fs/jfs/jfs_logmgr.h b/fs/jfs/jfs_logmgr.h index 09e0ef6aecce..d8858448de6f 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_inflight; + wait_queue_head_t io_waitq; }; /* -- 2.43.0