On Tue, Oct 28, 2014 at 03:09:56PM -0700, Paul E. McKenney wrote:
> From: Pranith Kumar <bobby.pr...@gmail.com>
>
> Got Paul's email wrong the first time.
>
> The map field in 'struct mapped_device' is an rcu pointer. Use
> rcu_dereference()
> while accessing it.
>
> Signed-off-by: Pranith Kumar <bobby.pr...@gmail.com>
> Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
On current -next I see this:
[ 6.388264] ===============================
[ 6.389571] [ INFO: suspicious RCU usage. ]
[ 6.390869] 3.18.0-rc5-next-20141121-08303-g44cae4530372 #2 Not tainted
[ 6.392185] -------------------------------
[ 6.393479] /home/kas/git/public/linux/drivers/md/dm.c:2853 suspicious
rcu_dereference_check() usage!
[ 6.394801]
other info that might help us debug this:
[ 6.398714]
rcu_scheduler_active = 1, debug_locks = 0
[ 6.401247] 1 lock held by cryptsetup/159:
[ 6.402522] #0: (&md->suspend_lock/1){+.+...}, at: [<ffffffff8179dd1d>]
dm_suspend+0x3d/0x140
[ 6.403848]
stack backtrace:
[ 6.406448] CPU: 3 PID: 159 Comm: cryptsetup Not tainted
3.18.0-rc5-next-20141121-08303-g44cae4530372 #2
[ 6.407726] Hardware name: LENOVO 3460CC6/3460CC6, BIOS G6ET93WW (2.53 )
02/04/2013
[ 6.408982] 0000000000000001 ffff8800d3ac7c38 ffffffff81b00bbd
0000000000000011
[ 6.410249] ffff8800d301a560 ffff8800d3ac7c68 ffffffff81153be7
ffff8800d3928800
[ 6.411548] ffff8800d3928970 ffff8800d3928aa0 0000000000000001
ffff8800d3ac7ca8
[ 6.412780] Call Trace:
[ 6.413980] [<ffffffff81b00bbd>] dump_stack+0x4c/0x6e
[ 6.415178] [<ffffffff81153be7>] lockdep_rcu_suspicious+0xe7/0x120
[ 6.416364] [<ffffffff8179de1d>] dm_suspend+0x13d/0x140
[ 6.417535] [<ffffffff817a2d80>] ? table_load+0x340/0x340
[ 6.418749] [<ffffffff817a2f2b>] dev_suspend+0x1ab/0x260
[ 6.419901] [<ffffffff817a2d80>] ? table_load+0x340/0x340
[ 6.421038] [<ffffffff817a3781>] ctl_ioctl+0x251/0x540
[ 6.422164] [<ffffffff812b6415>] ? mntput_no_expire+0x5/0x360
[ 6.423280] [<ffffffff817a3a83>] dm_ctl_ioctl+0x13/0x20
[ 6.424389] [<ffffffff812a6f98>] do_vfs_ioctl+0x308/0x540
[ 6.425515] [<ffffffff81175d2d>] ? rcu_read_lock_held+0x6d/0x70
[ 6.426601] [<ffffffff812b324e>] ? __fget_light+0xbe/0xd0
[ 6.427686] [<ffffffff812a7251>] SyS_ioctl+0x81/0xa0
[ 6.428760] [<ffffffff81b0d6ad>] system_call_fastpath+0x16/0x1b
--
Kirill A. Shutemov
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