Changbin Du 679fd3ebab drm/i915/gvt: Fix unsafe locking caused by spin_unlock_bh
The caller of shadow_context_status_change may disable irqs. So it is not
safe to use spin_unlock_bh in such context. Let's switch to irqsave version
for safety.

------------[ cut here ]------------
WARNING: CPU: 2 PID: 4504 at kernel/softirq.c:161 __local_bh_enable_ip+0x46/0x60
[  168.797710] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.2.8 01/26/2016
[  168.797712] task: ffff8c693d22db80 task.stack: ffffb51b482bc000
[  168.797718] RIP: 0010:__local_bh_enable_ip+0x46/0x60
[  168.797721] RSP: 0018:ffffb51b482bfa10 EFLAGS: 00010046
[  168.797724] RAX: 0000000000000046 RBX: ffff8c6900278000 RCX: 00000000ffffffff
[  168.797726] RDX: 0000000000000001 RSI: 0000000000000200 RDI: ffffffffc06a0330
[  168.797728] RBP: ffffb51b482bfa10 R08: 0000000000000000 R09: ffff8c690027cb90
[  168.797730] R10: ffffb51b482bfa40 R11: 00000004072f0001 R12: 0000000000000000
[  168.797732] R13: 0000000000000000 R14: ffff8c690027ca9c R15: 0000000000000000
[  168.797735] FS:  00007ff187c56700(0000) GS:ffff8c6959d00000(0000) knlGS:0000000000000000
[  168.797738] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  168.797740] CR2: 0000562bc0c3991f CR3: 0000000430614006 CR4: 00000000003606e0
[  168.797742] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  168.797744] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  168.797745] Call Trace:
[  168.797755]  _raw_spin_unlock_bh+0x1e/0x20
[  168.797826]  shadow_context_status_change+0x120/0x1e0 [i915]
[  168.797831]  notifier_call_chain+0x4a/0x70
[  168.797834]  atomic_notifier_call_chain+0x1a/0x20
[  168.797896]  execlists_cancel_port_requests+0x4f/0x80 [i915]
[  168.797956]  reset_common_ring+0x30/0x100 [i915]
[  168.798007]  i915_gem_reset_engine+0x114/0x330 [i915]
[  168.798060]  ? i915_gem_retire_requests+0x75/0x180 [i915]
[  168.798111]  i915_gem_reset+0x3e/0xb0 [i915]
[  168.798149]  i915_reset+0x10b/0x1c0 [i915]
[  168.798187]  i915_reset_device+0x209/0x220 [i915]
[  168.798225]  ? gen8_gt_irq_ack+0x170/0x170 [i915]
[  168.798229]  ? __queue_work+0x430/0x430
[  168.798270]  i915_handle_error+0x285/0x420 [i915]
[  168.798275]  ? mntput+0x24/0x40
[  168.798281]  ? terminate_walk+0x8e/0xf0
[  168.798328]  i915_wedged_set+0x84/0xc0 [i915]
[  168.798333]  simple_attr_write+0xab/0xc0
[  168.798337]  full_proxy_write+0x54/0x90
[  168.798343]  __vfs_write+0x37/0x170
[  168.798349]  ? common_file_perm+0x4c/0x100
[  168.798355]  ? apparmor_file_permission+0x1a/0x20
[  168.798361]  ? security_file_permission+0x3b/0xc0
[  168.798365]  vfs_write+0xb8/0x1b0
[  168.798370]  SyS_write+0x55/0xc0
[  168.798376]  entry_SYSCALL_64_fastpath+0x1e/0xa9

Fixes: 0e86cc9 ("drm/i915/gvt: implement per-vm mmio switching optimization")
Signed-off-by: Changbin Du <changbin.du@intel.com>

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
2017-11-28 17:22:48 +08:00
2005-09-10 10:06:29 -07:00
2017-11-26 16:01:47 -08:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
Description
No description provided
Readme 7.8 GiB
Languages
C 97.7%
Assembly 1.6%
Makefile 0.3%
Perl 0.1%