From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f70.google.com (mail-oa1-f70.google.com [209.85.160.70]) (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 53D5438D3FB for ; Thu, 14 May 2026 23:35:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778801753; cv=none; b=PEztz4OfltVj9BpXQBOAkNaIGt+Amv0OUny7603zJSSHiA742RXl/xvXpBERyc4INGTECiDnH+rIslfhAbvx1rxqsosJzwQssEsPedaa+EKDKCjAB7FNfzvmVy7HSB9nmnQcApV9FUftFexSJxjbMvAVgVOI9/1XkKtLxTYxcS4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778801753; c=relaxed/simple; bh=0pGOWR9cc1koPXSXKd8qi85ZS653bJEDDFb/rnFfBRs=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=oRiCffuE2Ka/gEYPVyqwQqClHtBKD8ReNvo2is7ji3Is5myM/e1235Lob4eFDnllmyi0i2AS7SfY9zbTZbYVythH83no5AEM0eXJ0rcYzGL2NXCsPngMOLNmBIFNbE6KdGRO6w38AKGzSQmdyKU/OlXx2QG0VkDbZdEcjVzUS1c= 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=209.85.160.70 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-oa1-f70.google.com with SMTP id 586e51a60fabf-439eef93638so3761472fac.2 for ; Thu, 14 May 2026 16:35:52 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1778801751; x=1779406551; 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=sMFEGNqn+2oyb/FfLLKxBzGxNted6rzS1nPmIHjFmk8=; b=DlwnbMTH488RBVsJYZyoVK23GP53XzAuo1UQsNwxHD9yOmKXATGJcPy1iXMpW+LQMe bhPx9uNqQJfE+7S6qEBmArT0HA/hEgQLei4pvY9VuiuEgGHLT4V2vKSYKyarisbUCDUE qqIrj9Agw+ld9ZBC9pSVPSseAHqEGVVuSxCiGSsJkKTcQzKmmbUbbQjxSEp0L4gVeO8D sygatMXG0dg5DXfmNZ+gB19DsoIqRQ0/D0PbIORHLqQCgTNWgqVrbMpAG/Ce+OyRLPES 0HZUXDz/k1SDJQPeemV4By/aTsHcFtDweE1veQBHazfijz5BRknnFTsG1pqU+fjJaL9+ i80g== X-Gm-Message-State: AOJu0YyyGXys+MfgxGuDAb68w4DZ3S5zLoKHrPcPd7CZYTq1VluiZrjf uoGlutIiW4ljTWM13Rrd7v0eQscZVnRhcUpxvL9l0xofCy5ub5PHZqx5GrA/wqJdENx4cHlCvU6 0y4h3qTmXfLuKQucNtZ9qTvz37LIZepj+FwzZOSCOHIGwM9RjZ2qOso7CbzY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1620:b0:69b:408a:4b18 with SMTP id 006d021491bc7-69c942b431emr1072917eaf.9.1778801751341; Thu, 14 May 2026 16:35:51 -0700 (PDT) Date: Thu, 14 May 2026 16:35:51 -0700 In-Reply-To: <6a062e5c.170a0220.196691.0007.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a065c57.050a0220.d11c8.0019.GAE@google.com> Subject: Forwarded: [PATCH] f2fs: DEBUG: trace node folio lifecycle to diagnose write_end_io BUG 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: [PATCH] f2fs: DEBUG: trace node folio lifecycle to diagnose write_end_io BUG Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master Not for upstream. Instrumentation to identify which path leaves a node folio with folio->index != nid_of_node(folio) at writeback time, triggering the BUG in f2fs_write_end_io() reported by syzbot. Adds pr_info trace points at: - f2fs_new_node_folio() - in-memory node folio construction - __get_node_folio() - node folio lookup (cache or read) - __get_node_folio() - synchronous footer sanity failure - f2fs_finish_read_bio() - async read completion footer check - f2fs_write_end_io() - write completion footer check BUG_ON in f2fs_write_end_io() is intentionally retained so the kernel halts at the failing folio and the preceding pr_info output appears in the syzbot console log. Link: https://syzkaller.appspot.com/bug?extid=4af46ee83100e99bce09 Not-Signed-off-by: Deepanshu Kartikey --- fs/f2fs/data.c | 19 ++++++++++++++----- fs/f2fs/node.c | 5 +++++ 2 files changed, 19 insertions(+), 5 deletions(-) diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 8d4f1e75dee3..dc01a4fe089a 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -174,10 +174,17 @@ static void f2fs_finish_read_bio(struct bio *bio, bool in_task) dec_page_count(F2FS_F_SB(folio), __read_io_type(folio)); if (bio->bi_status == BLK_STS_OK && - F2FS_F_SB(folio)->node_inode && is_node_folio(folio) && - f2fs_sanity_check_node_footer(F2FS_F_SB(folio), - folio, folio->index, NODE_TYPE_REGULAR, true)) - bio->bi_status = BLK_STS_IOERR; + F2FS_F_SB(folio)->node_inode && is_node_folio(folio)) { + int rc = f2fs_sanity_check_node_footer(F2FS_F_SB(folio), + folio, folio->index, NODE_TYPE_REGULAR, true); + pr_info("f2fs-dbg: READ end_io: index=%lu footer_nid=%u ino=%u rc=%d\n", + folio->index, + nid_of_node(folio), + ino_of_node(folio), + rc); + if (rc) + bio->bi_status = BLK_STS_IOERR; + } if (finished) folio_end_read(folio, bio->bi_status == BLK_STS_OK); @@ -383,8 +390,10 @@ static void f2fs_write_end_io(struct bio *bio) } if (is_node_folio(folio)) { - f2fs_sanity_check_node_footer(sbi, folio, + int rc = f2fs_sanity_check_node_footer(sbi, folio, folio->index, NODE_TYPE_REGULAR, true); + pr_info("f2fs-dbg: WRITE end_io: index=%lu footer_nid=%u ino=%u rc=%d\n", + folio->index,nid_of_node(folio),ino_of_node(folio),rc); f2fs_bug_on(sbi, folio->index != nid_of_node(folio)); } if (f2fs_in_warm_node_list(folio)) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 4e5bd9e4cfc3..12a9774ac1df 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1423,6 +1423,8 @@ struct folio *f2fs_new_node_folio(struct dnode_of_data *dn, unsigned int ofs) f2fs_folio_wait_writeback(folio, NODE, true, true); fill_node_footer(folio, dn->nid, dn->inode->i_ino, ofs, true); set_cold_node(folio, S_ISDIR(dn->inode->i_mode)); + pr_info("f2fs-dbg: NEW node_folio: nid=%u ino=%lu ofs=%u\n", + dn->nid, dn->inode->i_ino, ofs); if (!folio_test_uptodate(folio)) folio_mark_uptodate(folio); if (folio_mark_dirty(folio)) @@ -1565,6 +1567,7 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, struct folio *folio; int err; + pr_info("f2fs-dbg: GET node_folio: nid=%lu ntype=%d\n", nid, ntype); if (!nid) return ERR_PTR(-ENOENT); if (f2fs_check_nid_range(sbi, nid)) @@ -1603,6 +1606,8 @@ static struct folio *__get_node_folio(struct f2fs_sb_info *sbi, pgoff_t nid, err = f2fs_sanity_check_node_footer(sbi, folio, nid, ntype, false); if (!err) return folio; + pr_info("f2fs-dbg: SYNC sanity fail: nid=%lu footer_nid=%u ino=%u err=%d\n", + nid,nid_of_node(folio),ino_of_node(folio),err); out_err: folio_clear_uptodate(folio); out_put_err: -- 2.43.0