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Fri, 22 Oct 2021 01:35:34 +0000 Received: from pps.filterd (m0246573.ppops.net [127.0.0.1]) by mx0b-00069f01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 19LJrPhD003967 for ; Fri, 22 Oct 2021 01:35:33 GMT Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by mx0b-00069f01.pphosted.com with ESMTP id 3budq3m4cf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Fri, 22 Oct 2021 01:35:33 +0000 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R131e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04407; MF=joseph.qi@linux.alibaba.com; NM=1; PH=DS; RN=5; SR=0; TI=SMTPD_---0UtCQSR9_1634866525; Received: from B-D1K7ML85-0059.local(mailfrom:joseph.qi@linux.alibaba.com fp:SMTPD_---0UtCQSR9_1634866525) by smtp.aliyun-inc.com(127.0.0.1); Fri, 22 Oct 2021 09:35:26 +0800 To: Gautham Ananthakrishna , ocfs2-devel@oss.oracle.com, akpm References: <1634820718-6043-1-git-send-email-gautham.ananthakrishna@oracle.com> From: Joseph Qi Message-ID: <47e7ddf7-8d0b-0101-69ca-eaecc5fa1813@linux.alibaba.com> Date: Fri, 22 Oct 2021 09:35:25 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <1634820718-6043-1-git-send-email-gautham.ananthakrishna@oracle.com> Content-Language: en-US X-Source-IP: 115.124.30.45 X-ServerName: out30-45.freemail.mail.aliyun.com X-Proofpoint-SPF-Result: pass X-Proofpoint-SPF-Record: v=spf1 include:spf1.service.alibaba.com include:spf2.service.alibaba.com include:spf1.ocm.aliyun.com include:spf2.ocm.aliyun.com include:spf1.staff.mail.aliyun.com include:a.hichina.mail.aliyun.com include:b.hichina.mail.aliyun.com -all X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10144 signatures=668683 X-Proofpoint-Spam-Details: rule=tap_notspam policy=tap score=0 suspectscore=0 mlxlogscore=999 phishscore=0 lowpriorityscore=0 malwarescore=0 mlxscore=0 spamscore=0 priorityscore=130 impostorscore=0 bulkscore=0 clxscore=284 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109230001 definitions=main-2110220006 domainage_hfrom=8226 X-Spam: Clean Cc: rajesh.sivaramasubramaniom@oracle.com Subject: Re: [Ocfs2-devel] [PATCH V2 RFC 1/1] ocfs2: race between searching chunks and release journal_head from buffer_head X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10144 signatures=668683 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 mlxscore=0 adultscore=0 spamscore=0 phishscore=0 bulkscore=0 suspectscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109230001 definitions=main-2110220006 X-Proofpoint-ORIG-GUID: XxVg9IkmPTh19DQgbfyz_xludbNMssN9 X-Proofpoint-GUID: XxVg9IkmPTh19DQgbfyz_xludbNMssN9 On 10/21/21 8:51 PM, Gautham Ananthakrishna wrote: > Encountered a race between ocfs2_test_bg_bit_allocatable() and > jbd2_journal_put_journal_head() resulting in the below vmcore. > > PID: 106879 TASK: ffff880244ba9c00 CPU: 2 COMMAND: "loop3" > 0 [ffff8802435ff1c0] panic at ffffffff816ed175 > 1 [ffff8802435ff240] oops_end at ffffffff8101a7c9 > 2 [ffff8802435ff270] no_context at ffffffff8106eccf > 3 [ffff8802435ff2e0] __bad_area_nosemaphore at ffffffff8106ef9d > 4 [ffff8802435ff330] bad_area_nosemaphore at ffffffff8106f143 > 5 [ffff8802435ff340] __do_page_fault at ffffffff8106f80b > 6 [ffff8802435ff3a0] do_page_fault at ffffffff8106fc2f > 7 [ffff8802435ff3e0] page_fault at ffffffff816fd667 > [exception RIP: ocfs2_block_group_find_clear_bits+316] > RIP: ffffffffc11ef6fc RSP: ffff8802435ff498 RFLAGS: 00010206 > RAX: 0000000000003918 RBX: 0000000000000001 RCX: 0000000000000018 > RDX: 0000000000003918 RSI: 0000000000000000 RDI: ffff880060194040 > RBP: ffff8802435ff4f8 R8: ffffffffff000000 R9: ffffffffffffffff > R10: ffff8802435ff730 R11: ffff8802a94e5800 R12: 0000000000000007 > R13: 0000000000007e00 R14: 0000000000003918 R15: ffff88017c973a28 > ORIG_RAX: ffffffffffffffff CS: e030 SS: e02b > 8 [ffff8802435ff490] ocfs2_block_group_find_clear_bits at ffffffffc11ef680 [ocfs2] > 9 [ffff8802435ff500] ocfs2_cluster_group_search at ffffffffc11ef916 [ocfs2] > 10 [ffff8802435ff580] ocfs2_search_chain at ffffffffc11f0fb6 [ocfs2] > 11 [ffff8802435ff660] ocfs2_claim_suballoc_bits at ffffffffc11f1b1b [ocfs2] > 12 [ffff8802435ff6f0] __ocfs2_claim_clusters at ffffffffc11f32cb [ocfs2] > 13 [ffff8802435ff770] ocfs2_claim_clusters at ffffffffc11f5caf [ocfs2] > 14 [ffff8802435ff780] ocfs2_local_alloc_slide_window at ffffffffc11cc0db [ocfs2] > 15 [ffff8802435ff820] ocfs2_reserve_local_alloc_bits at ffffffffc11ce53f [ocfs2] > 16 [ffff8802435ff890] ocfs2_reserve_clusters_with_limit at ffffffffc11f59b5 [ocfs2] > 17 [ffff8802435ff8e0] ocfs2_reserve_clusters at ffffffffc11f5c88 [ocfs2] > 18 [ffff8802435ff8f0] ocfs2_lock_refcount_allocators at ffffffffc11dc169 [ocfs2] > 19 [ffff8802435ff960] ocfs2_make_clusters_writable at ffffffffc11e4274 [ocfs2] > 20 [ffff8802435ffa50] ocfs2_replace_cow at ffffffffc11e4df1 [ocfs2] > 21 [ffff8802435ffac0] ocfs2_refcount_cow at ffffffffc11e54b1 [ocfs2] > 22 [ffff8802435ffb80] ocfs2_file_write_iter at ffffffffc11bf8f4 [ocfs2] > 23 [ffff8802435ffcd0] lo_rw_aio at ffffffff814a1b5d > 24 [ffff8802435ffd80] loop_queue_work at ffffffff814a2802 > 25 [ffff8802435ffe60] kthread_worker_fn at ffffffff810a80d2 > 26 [ffff8802435ffec0] kthread at ffffffff810a7afb > 27 [ffff8802435fff50] ret_from_fork at ffffffff816f7da1 > > When ocfs2_test_bg_bit_allocatable() called bh2jh(bg_bh), the bg_bh->b_private > NULL as jbd2_journal_put_journal_head() raced and released the jounal head > from the buffer head. Needed to take bit lock for the bit 'BH_JournalHead' > to fix this race. > > Signed-off-by: Gautham Ananthakrishna Reviewed-by: Joseph Qi > --- > fs/ocfs2/suballoc.c | 22 +++++++++++++--------- > 1 file changed, 13 insertions(+), 9 deletions(-) > > diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c > index 8521942..481017e 100644 > --- a/fs/ocfs2/suballoc.c > +++ b/fs/ocfs2/suballoc.c > @@ -1251,7 +1251,7 @@ static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh, > { > struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data; > struct journal_head *jh; > - int ret; > + int ret = 1; > > if (ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap)) > return 0; > @@ -1259,14 +1259,18 @@ static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh, > if (!buffer_jbd(bg_bh)) > return 1; > > - jh = bh2jh(bg_bh); > - spin_lock(&jh->b_state_lock); > - bg = (struct ocfs2_group_desc *) jh->b_committed_data; > - if (bg) > - ret = !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap); > - else > - ret = 1; > - spin_unlock(&jh->b_state_lock); > + jbd_lock_bh_journal_head(bg_bh); > + if (buffer_jbd(bg_bh)) { > + jh = bh2jh(bg_bh); > + spin_lock(&jh->b_state_lock); > + bg = (struct ocfs2_group_desc *) jh->b_committed_data; > + if (bg) > + ret = !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap); > + else > + ret = 1; > + spin_unlock(&jh->b_state_lock); > + } > + jbd_unlock_bh_journal_head(bg_bh); > > return ret; > } > _______________________________________________ Ocfs2-devel mailing list Ocfs2-devel@oss.oracle.com https://oss.oracle.com/mailman/listinfo/ocfs2-devel