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From:   Bo Ye <bo.ye@mediatek.com>
To:     Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
CC:     <yongdong.zhang@mediatek.com>, <peng.zhou@mediatek.com>,
        <browse.zhang@mediatek.com>, <light.hsieh@mediatek.com>,
        Qilin Tan <qilin.tan@mediatek.com>,
        <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-mediatek@lists.infradead.org>
Subject: [PATCH 1/2] f2fs: fix iostat lock protection
Date:   Fri, 31 Mar 2023 17:26:56 +0800
Message-ID: <20230331092658.72386-1-bo.ye@mediatek.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

From: Qilin Tan <qilin.tan@mediatek.com>

Made iostat lock irq safe to avoid potentinal deadlock.

Deadlock scenario:
f2fs_attr_store
  -> f2fs_sbi_store
  -> _sbi_store
  -> spin_lock(sbi->iostat_lock)
    <interrupt request>
    -> scsi_end_request
    -> bio_endio
    -> f2fs_dio_read_end_io
    -> f2fs_update_iostat
    -> spin_lock_irqsave(sbi->iostat_lock)  ===> Dead lock here

Signed-off-by: Qilin Tan <qilin.tan@mediatek.com>
---
 fs/f2fs/sysfs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 0b19163c90d4..fd238a68017e 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -575,9 +575,9 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 	if (!strcmp(a->attr.name, "iostat_period_ms")) {
 		if (t < MIN_IOSTAT_PERIOD_MS || t > MAX_IOSTAT_PERIOD_MS)
 			return -EINVAL;
-		spin_lock(&sbi->iostat_lock);
+		spin_lock_irq(&sbi->iostat_lock);
 		sbi->iostat_period_ms = (unsigned int)t;
-		spin_unlock(&sbi->iostat_lock);
+		spin_unlock_irq(&sbi->iostat_lock);
 		return count;
 	}
 #endif
-- 
2.17.0