Re: VFS deadlock ?

From: Al Viro
Date: Thu Mar 21 2013 - 15:21:52 EST


On Thu, Mar 21, 2013 at 03:06:53PM -0400, Dave Jones wrote:
> Al, Linus,

> trinity-child2 D ffff880110b3a7e0 5448 7669 1 0x00000004
[sits in rename(), trying to grab ->i_mutex on a parent]

> Showing all locks held in the system:
> 4 locks on stack by trinity-child2/7669:
> #0: blocked: (sb_writers#4){.+.+.+}, instance: ffff8801292d17d8, at: [<ffffffff811df134>] mnt_want_write+0x24/0x50
> #1: held: (&type->s_vfs_rename_key){+.+.+.}, instance: ffff8801292d1928, at: [<ffffffff811c6f5e>] lock_rename+0x3e/0x120
> #2: held: (&type->i_mutex_dir_key#2/1){+.+.+.}, instance: ffff880110b3a858, at: [<ffffffff811c701e>] lock_rename+0xfe/0x120
> #3: blocked: (&type->i_mutex_dir_key#2/2){+.+.+.}, instance: ffff880110b3a858, at: [<ffffffff811c7034>] lock_rename+0x114/0x120

Wait a minute... How the hell does it manage to sit with *two* blocked locks?
Confused...
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/