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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Minchan Kim <minchan@kernel.org>,
	Sasha Levin <sasha.levin@oracle.com>,
	"Alexander E. Patrakov" <patrakov@gmail.com>,
	Nitin Gupta <ngupta@vflare.org>,
	Jerome Marchand <jmarchan@redhat.com>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: [PATCH 3.15 16/37] zram: avoid lockdep splat by revalidate_disk
Date: Tue, 29 Jul 2014 18:48:52 -0700	[thread overview]
Message-ID: <20140730014828.467162387@linuxfoundation.org> (raw)
In-Reply-To: <20140730014827.565626091@linuxfoundation.org>

3.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Minchan Kim <minchan@kernel.org>

commit b4c5c60920e3b0c4598f43e7317559f6aec51531 upstream.

Sasha reported lockdep warning [1] introduced by [2].

It could be fixed by doing disk revalidation out of the init_lock.  It's
okay because disk capacity change is protected by init_lock so that
revalidate_disk always sees up-to-date value so there is no race.

[1] https://lkml.org/lkml/2014/7/3/735
[2] zram: revalidate disk after capacity change

Fixes 2e32baea46ce ("zram: revalidate disk after capacity change").

Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Cc: "Alexander E. Patrakov" <patrakov@gmail.com>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/block/zram/zram_drv.c |   22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -622,11 +622,18 @@ static void zram_reset_device(struct zra
 	memset(&zram->stats, 0, sizeof(zram->stats));
 
 	zram->disksize = 0;
-	if (reset_capacity) {
+	if (reset_capacity)
 		set_capacity(zram->disk, 0);
-		revalidate_disk(zram->disk);
-	}
+
 	up_write(&zram->init_lock);
+
+	/*
+	 * Revalidate disk out of the init_lock to avoid lockdep splat.
+	 * It's okay because disk's capacity is protected by init_lock
+	 * so that revalidate_disk always sees up-to-date capacity.
+	 */
+	if (reset_capacity)
+		revalidate_disk(zram->disk);
 }
 
 static ssize_t disksize_store(struct device *dev,
@@ -666,8 +673,15 @@ static ssize_t disksize_store(struct dev
 	zram->comp = comp;
 	zram->disksize = disksize;
 	set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT);
-	revalidate_disk(zram->disk);
 	up_write(&zram->init_lock);
+
+	/*
+	 * Revalidate disk out of the init_lock to avoid lockdep splat.
+	 * It's okay because disk's capacity is protected by init_lock
+	 * so that revalidate_disk always sees up-to-date capacity.
+	 */
+	revalidate_disk(zram->disk);
+
 	return len;
 
 out_destroy_comp:



  parent reply	other threads:[~2014-07-30  1:52 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-30  1:48 [PATCH 3.15 00/37] 3.15.8-stable review Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 01/37] media: staging: tighten omap4iss dependencies Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 02/37] media: media: v4l2-core: v4l2-dv-timings.c: Cleaning up code wrong value used in aspect ratio Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 03/37] media: af9035: override tuner id when bad value set into eeprom Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 04/37] media: hdpvr: fix two audio bugs Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 05/37] media: tda10071: force modulation to QPSK on DVB-S Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 06/37] nfs: only show Posix ACLs in listxattr if actually present Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 07/37] xtensa: fix sysmem reservation at the end of existing block Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 08/37] block: provide compat ioctl for BLKZEROOUT Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 09/37] block: dont assume last put of shared tags is for the host Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 10/37] libata: support the ata host which implements a queue depth less than 32 Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 11/37] libata: introduce ata_host->n_tags to avoid oops on SAS controllers Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 12/37] s390/ptrace: fix PSW mask check Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 13/37] ahci: add support for the Promise FastTrak TX8660 SATA HBA (ahci mode) Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 14/37] blkcg: dont call into policy draining if root_blkg is already gone Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 15/37] tracing: Fix wraparound problems in "uptime" trace clock Greg Kroah-Hartman
2014-07-30  1:48 ` Greg Kroah-Hartman [this message]
2014-07-30  1:48 ` [PATCH 3.15 17/37] powerpc/pseries: dynamically added OF nodes need to call of_node_init Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 18/37] slab_common: fix the check for duplicate slab names Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 19/37] Input: synaptics - add min/max quirk for pnp-id LEN2002 (Edge E531) Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 20/37] Input: fix defuzzing logic Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 21/37] coredump: fix the setting of PF_DUMPCORE Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 22/37] fuse: s_time_gran fix Greg Kroah-Hartman
2014-07-30  1:48 ` [PATCH 3.15 23/37] fuse: add FUSE_NO_OPEN_SUPPORT flag to INIT Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 24/37] pinctrl: st: Fix irqmux handler Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 25/37] parisc: Remove SA_RESTORER define Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 26/37] hwmon: (smsc47m192) Fix temperature limit and vrm write operations Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 27/37] parport: fix menu breakage Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 28/37] fs: umount on symlink leaks mnt count Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 29/37] x86_32, entry: Store badsys error code in %eax Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 32/37] mm: hugetlb: fix copy_hugetlb_page_range() Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 34/37] hwrng: virtio - ensure reads happen after successful probe Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 35/37] mm: do not call do_fault_around for non-linear fault Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 36/37] nl80211: move set_qos_map command into split state Greg Kroah-Hartman
2014-07-30  1:49 ` [PATCH 3.15 37/37] platform_get_irq: Revert to platform_get_resource if of_irq_get fails Greg Kroah-Hartman
     [not found] ` <20140730014829.344302554@linuxfoundation.org>
2014-07-30  6:53   ` [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler Jakub Jelinek
2014-07-30  7:13     ` Markus Trippelsdorf
2014-07-30  7:21       ` Jakub Jelinek
2014-07-30  7:27         ` Markus Trippelsdorf
2014-07-30 15:47     ` Linus Torvalds
2014-08-05 11:31       ` Josh Boyer
2014-08-05 11:46         ` Markus Trippelsdorf
2014-08-05 15:24           ` Jakub Jelinek
2014-08-05 15:19         ` Greg Kroah-Hartman
2014-08-05 16:49         ` Linus Torvalds
2014-08-05 20:57           ` Josh Boyer
2014-08-05 21:07             ` Frank Ch. Eigler
2014-08-05 22:36               ` Linus Torvalds
2014-08-05 23:30                 ` Frank Ch. Eigler
2014-08-05 23:59                   ` Linus Torvalds
2014-10-06 21:05                     ` [PATCH] Kbuild: Add an option to enable GCC VTA Josh Stone
2014-08-06  8:14                 ` [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler Jakub Jelinek
2014-08-06 10:23                   ` Måns Rullgård
2014-08-06 10:23                     ` Måns Rullgård
2014-08-06 16:34                   ` Alexei Starovoitov
2014-07-30 11:58 ` [PATCH 3.15 00/37] 3.15.8-stable review Satoru Takeuchi
2014-07-30 11:58   ` Satoru Takeuchi
2014-07-30 15:50   ` Greg Kroah-Hartman
2014-07-30 16:09 ` Guenter Roeck
2014-07-30 22:23   ` Greg Kroah-Hartman

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