Re: __blkg_lookup oops with 4.2-rcX
From: Tejun Heo
Date: Sat Sep 05 2015 - 14:38:33 EST
On Sat, Sep 05, 2015 at 04:48:40PM +0100, Richard W.M. Jones wrote:
> On Sat, Sep 05, 2015 at 04:34:39PM +0100, Richard W.M. Jones wrote:
> > [ 52.259269] BUG: unable to handle kernel NULL pointer dereference at 00000000000009c8
> > [ 52.259269] IP: [<ffffffff813f8b10>] __blkg_lookup+0x40/0xe0
> And also:
> $ addr2line -e /usr/lib/debug/lib/modules/4.3.0-0.rc0.git7.1.rwmj3.fc24.x86_64/vmlinux ffffffff813f8b10
> 152 /*
> 153 * Hint didn't match. Look up from the radix tree. Note that the
> 154 * hint can only be updated under queue_lock as otherwise @blkg
> 155 * could have already been removed from blkg_tree. The caller is
> 156 * responsible for grabbing queue_lock if @update_hint.
> 157 */
> 158 blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
Okay, found the bug. It was an existing problem which got exposed by
the recent bypass change. Will soon post a patch.
Thanks a lot!
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/