Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
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.
Weinan Li
authored
Fix the suspicious RCU usage issue in intel_vgpu_emulate_mmio_write.
Here need to request the srcu read lock of kvm->srcu before doing
gfn_to_memslot(). The detailed log is as below:
[ 218.710688] =============================
[ 218.710690] WARNING: suspicious RCU usage
[ 218.710693] 4.14.15-dd+ #314 Tainted: G U
[ 218.710695] -----------------------------
[ 218.710697] ./include/linux/kvm_host.h:575 suspicious rcu_dereference_check() usage!
[ 218.710699]
other info that might help us debug this:
[ 218.710702]
rcu_scheduler_active = 2, debug_locks = 1
[ 218.710704] 1 lock held by qemu-system-x86/2144:
[ 218.710706] #0: (&gvt->lock){+.+.}, at: [<ffffffff816a1eea>] intel_vgpu_emulate_mmio_write+0x5a/0x2d0
[ 218.710721]
stack backtrace:
[ 218.710724] CPU: 0 PID: 2144 Comm: qemu-system-x86 Tainted: G U 4.14.15-dd+ #314
[ 218.710727] Hardware name: Dell Inc. OptiPlex 7040/0Y7WYT, BIOS 1.1.1 10/07/2015
[ 218.710729] Call Trace:
[ 218.710734] dump_stack+0x7c/0xb3
[ 218.710739] gfn_to_memslot+0x15f/0x170
[ 218.710743] kvm_is_visible_gfn+0xa/0x30
[ 218.710746] intel_vgpu_emulate_gtt_mmio_write+0x267/0x3c0
[ 218.710751] ? __mutex_unlock_slowpath+0x3b/0x260
[ 218.710754] intel_vgpu_emulate_mmio_write+0x182/0x2d0
[ 218.710759] intel_vgpu_rw+0xba/0x170 [kvmgt]
[ 218.710763] intel_vgpu_write+0x14d/0x1a0 [kvmgt]
[ 218.710767] __vfs_write+0x23/0x130
[ 218.710770] vfs_write+0xb0/0x1b0
[ 218.710774] SyS_pwrite64+0x73/0x90
[ 218.710777] entry_SYSCALL_64_fastpath+0x25/0x9c
[ 218.710780] RIP: 0033:0x7f33e8a91da3
[ 218.710783] RSP: 002b:00007f33dddc8700 EFLAGS: 00000293
v2: add 'Fixes' tag, refine log format.(Zhenyu)
Fixes: cc753fbe
("drm/i915/gvt: validate gfn before set shadow page")
Reviewed-by: 
Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: 
Weinan Li <weinan.z.li@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>| Name | Last commit | Last update |
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