From: Aneesh Kumar K.V Date: Tue, 10 Sep 2013 13:14:42 +0000 (+0530) Subject: powerpc: Fix possible deadlock on page fault X-Git-Tag: v3.12-rc1~59^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=69e044dd759e26667c110ab771d2c908fbd5d3dd;p=pandora-kernel.git powerpc: Fix possible deadlock on page fault stack_grow_into/14082 is trying to acquire lock: (&mm->mmap_sem){++++++}, at: [] .might_fault+0x78/0xe0 but task is already holding lock: (&mm->mmap_sem){++++++}, at: [] .do_page_fault+0x24c/0x910 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&mm->mmap_sem); lock(&mm->mmap_sem); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by stack_grow_into/14082: #0: (&mm->mmap_sem){++++++}, at: [] .do_page_fault+0x24c/0x910 stack backtrace: CPU: 21 PID: 14082 Comm: stack_grow_into Not tainted 3.10.0-10.el7.ppc64.debug #1 Call Trace: [c0000003d396b850] [c000000000016e7c] .show_stack+0x7c/0x1f0 (unreliable) [c0000003d396b920] [c000000000813fc8] .dump_stack+0x28/0x3c [c0000003d396b990] [c000000000124b90] .__lock_acquire+0x1640/0x1800 [c0000003d396bab0] [c00000000012570c] .lock_acquire+0xac/0x250 [c0000003d396bb80] [c000000000206d54] .might_fault+0xa4/0xe0 [c0000003d396bbf0] [c0000000007ffe2c] .do_page_fault+0x2ec/0x910 [c0000003d396be30] [c0000000000092e8] handle_page_fault+0x10/0x30 Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt --- Reading git-diff-tree failed