mirror of
https://git.yoctoproject.org/meta-ti
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Koen Kooi
189ce92b4c
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
86 lines
2.8 KiB
Diff
86 lines
2.8 KiB
Diff
From 1e5cac540c54d687fea366251cc0ddf9266c0685 Mon Sep 17 00:00:00 2001
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From: Brian Norris <computersforpeace@gmail.com>
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Date: Mon, 7 Nov 2011 15:51:05 -0800
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Subject: [PATCH 003/129] mtd: mtd_blkdevs: don't increase 'open' count on
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error path
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commit 342ff28f5a2e5aa3236617bd2bddf6c749677ef2 upstream.
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Some error paths in mtd_blkdevs were fixed in the following commit:
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commit 94735ec4044a6d318b83ad3c5794e931ed168d10
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mtd: mtd_blkdevs: fix error path in blktrans_open
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But on these error paths, the block device's `dev->open' count is
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already incremented before we check for errors. This meant that, while
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the error path was handled correctly on the first time through
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blktrans_open(), the device is erroneously considered already open on
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the second time through.
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This problem can be seen, for instance, when a UBI volume is
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simultaneously mounted as a UBIFS partition and read through its
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corresponding gluebi mtdblockX device. This results in blktrans_open()
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passing its error checks (with `dev->open > 0') without actually having
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a handle on the device. Here's a summarized log of the actions and
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results with nandsim:
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# modprobe nandsim
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# modprobe mtdblock
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# modprobe gluebi
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# modprobe ubifs
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# ubiattach /dev/ubi_ctrl -m 0
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...
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# ubimkvol /dev/ubi0 -N test -s 16MiB
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...
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# mount -t ubifs ubi0:test /mnt
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# ls /dev/mtdblock*
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/dev/mtdblock0 /dev/mtdblock1
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# cat /dev/mtdblock1 > /dev/null
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cat: can't open '/dev/mtdblock4': Device or resource busy
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# cat /dev/mtdblock1 > /dev/null
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CPU 0 Unable to handle kernel paging request at virtual address
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fffffff0, epc == 8031536c, ra == 8031f280
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Oops[#1]:
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...
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Call Trace:
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[<8031536c>] ubi_leb_read+0x14/0x164
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[<8031f280>] gluebi_read+0xf0/0x148
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[<802edba8>] mtdblock_readsect+0x64/0x198
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[<802ecfe4>] mtd_blktrans_thread+0x330/0x3f4
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[<8005be98>] kthread+0x88/0x90
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[<8000bc04>] kernel_thread_helper+0x10/0x18
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Signed-off-by: Brian Norris <computersforpeace@gmail.com>
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Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com>
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Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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---
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drivers/mtd/mtd_blkdevs.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/drivers/mtd/mtd_blkdevs.c b/drivers/mtd/mtd_blkdevs.c
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index ed8b5e7..424ca5f 100644
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--- a/drivers/mtd/mtd_blkdevs.c
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+++ b/drivers/mtd/mtd_blkdevs.c
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@@ -215,7 +215,7 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
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mutex_lock(&dev->lock);
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- if (dev->open++)
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+ if (dev->open)
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goto unlock;
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kref_get(&dev->ref);
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@@ -235,6 +235,7 @@ static int blktrans_open(struct block_device *bdev, fmode_t mode)
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goto error_release;
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unlock:
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+ dev->open++;
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mutex_unlock(&dev->lock);
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blktrans_dev_put(dev);
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return ret;
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--
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1.7.9.5
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