For some peculiar reason rcuwait_wake_up() has the right barrier in
the comment, but not in the code.
This mistake has been observed to cause a deadlock in the following
situation:
P1 P2
percpu_up_read() percpu_down_write()
rcu_sync_is_idle() // false
rcu_sync_enter()
...
__percpu_up_read()
[S] ,- __this_cpu_dec(*sem->read_count)
| smp_rmb();
[L] | task = rcu_dereference(w->task) // NULL
|
| [S] w->task = current
| smp_mb();
| [L] readers_active_check() // fail
`-> <store happens here>
Where the smp_rmb() (obviously) fails to constrain the store.
[ peterz: Added changelog. ]
Signed-off-by: Prateek Sood <prsood@codeaurora.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 8f95c90ceb ("sched/wait, RCU: Introduce rcuwait machinery")
Link: https://lkml.kernel.org/r/1543590656-7157-1-git-send-email-prsood@codeaurora.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull rdma fixes frfom Jason Gunthorpe:
"Not much so far. We have the usual batch of bugs and two fixes to code
merged this cycle:
- Restore valgrind support for the ioctl verbs interface merged this
window, and fix a missed error code on an error path from that
conversion
- A user reported crash on obsolete mthca hardware
- pvrdma was using the wrong command opcode toward the hypervisor
- NULL pointer crash regression when dumping rdma-cm over netlink
- Be conservative about exposing the global rkey"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
RDMA/uverbs: Mark ioctl responses with UVERBS_ATTR_F_VALID_OUTPUT
RDMA/mthca: Clear QP objects during their allocation
RDMA/vmw_pvrdma: Return the correct opcode when creating WR
RDMA/cma: Add cm_id restrack resource based on kernel or user cm_id type
RDMA/nldev: Don't expose unsafe global rkey to regular user
RDMA/uverbs: Fix post send success return value in case of error
Pull drm fixes from Dave Airlie:
"The rc3 fixes are a bit scattered:
- meson, sun4i and rockchip all had missing of_node_put.
- qxl and virtio both were advertising dma-buf to userspace when they
really shouldn't have.
Otherwise:
meson:
- modesetting regression fix
i915 GVT:
- one cmd parser failure fix
- region cleanup fix in vGPU destroy
amdgpu:
- KFD fixes for arm64 mixed APU/DGPU
- vega12 powerplay fix
- raven DC fixes
- freesync fix"
* tag 'drm-fixes-2019-01-18' of git://anongit.freedesktop.org/drm/drm:
drm/amd/display: Detach backlight from stream
drm/sun4i: backend: add missing of_node_puts
Revert "drm/amdgpu: validate user pitch alignment"
Revert "drm/amdgpu: validate user GEM object size"
drm/meson: Fix atomic mode switching regression
drm/i915/gvt: Fix mmap range check
drm/i915/gvt: free VFIO region space in vgpu detach
drm/amd/display: Fix disabled cursor on top screen edge
drm/amd/display: fix warning on raven hotplug
drm/amd/display: fix PME notification not working in RV desktop
drm/amd/display: Only get the connector state for VRR when toggled
drm/amd/display: Pack DMCU iRAM alignment
drm/amd/powerplay: run acg btc for Vega12
drm/amdkfd: Don't assign dGPUs to APU topology devices
drm/amdkfd: Allow building KFD on ARM64 (v2)
drm/meson: add missing of_node_put
drm/virtio: drop prime import/export callbacks
drm/qxl: drop prime import/export callbacks
drm/i915/gvt: Allow F_CMD_ACCESS on mmio 0x21f0
drm/rockchip: add missing of_node_put
Pull LED fix from Jacek Anaszewski.
* tag 'led-fix-for-5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
leds: lp5523: fix a missing check of return value of lp55xx_read
Pull hwmon fixes from Guenter Roeck:
"Minor fixes/regressions"
* tag 'hwmon-for-v5.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: (tmp421) Correct the misspelling of the tmp442 compatible attribute in OF device ID table
hwmon: (occ) Fix potential integer overflow
hwmon: (lm80) Fix missing unlock on error in set_fan_div()
hwmon: (nct6775) Enable IO mapping for NCT6797D and NCT6798D
hwmon: (nct6775) Fix chip ID for NCT6798D
When lp55xx_read() fails, "status" is an uninitialized variable and thus
may contain random value; using it leads to undefined behaviors.
The fix inserts a check for the return value of lp55xx_read: if it
fails, returns with its error code.
Signed-off-by: Kangjie Lu <kjlu@umn.edu>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Pull AFS fixes from David Howells:
"Here's a set of fixes for AFS:
- Use struct_size() for kzalloc() size calculation.
- When calling YFS.CreateFile rather than AFS.CreateFile, it is
possible to create a file with a file lock already held. The
default value indicating no lock required is actually -1, not 0.
- Fix an oops in inode/vnode validation if the target inode doesn't
have a server interest assigned (ie. a server that will notify us
of changes by third parties).
- Fix refcounting of keys in file locking.
- Fix a race in refcounting asynchronous operations in the event of
an error during request transmission. The provision of a dedicated
function to get an extra ref on a call is split into a separate
commit"
* tag 'afs-fixes-20190117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
afs: Fix race in async call refcounting
afs: Provide a function to get a ref on a call
afs: Fix key refcounting in file locking code
afs: Don't set vnode->cb_s_break in afs_validate()
afs: Set correct lock type for the yfs CreateFile
afs: Use struct_size() in kzalloc()
Pull swiotlb fix from Konrad Rzeszutek Wilk:
"A tiny fix for v5.0-rc2:
This fixes an issue with GPU cards not working anymore with the DMA
mapping work Christopher did - as the SWIOTLB is initialized first and
then free'd (as IOMMU is available) but we forgot to clear our start
and end entries which are used and BOOM"
* 'stable/for-linus-5.0' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb:
swiotlb: clear io_tlb_start and io_tlb_end in swiotlb_exit
There's a race between afs_make_call() and afs_wake_up_async_call() in the
case that an error is returned from rxrpc_kernel_send_data() after it has
queued the final packet.
afs_make_call() will try and clean up the mess, but the call state may have
been moved on thereby causing afs_process_async_call() to also try and to
delete the call.
Fix this by:
(1) Getting an extra ref for an asynchronous call for the call itself to
hold. This makes sure the call doesn't evaporate on us accidentally
and will allow the call to be retained by the caller in a future
patch. The ref is released on leaving afs_make_call() or
afs_wait_for_call_to_complete().
(2) In the event of an error from rxrpc_kernel_send_data():
(a) Don't set the call state to AFS_CALL_COMPLETE until *after* the
call has been aborted and ended. This prevents
afs_deliver_to_call() from doing anything with any notifications
it gets.
(b) Explicitly end the call immediately to prevent further callbacks.
(c) Cancel any queued async_work and wait for the work if it's
executing. This allows us to be sure the race won't recur when we
change the state. We put the work queue's ref on the call if we
managed to cancel it.
(d) Put the call's ref that we got in (1). This belongs to us as long
as the call is in state AFS_CALL_CL_REQUESTING.
Fixes: 341f741f04 ("afs: Refcount the afs_call struct")
Signed-off-by: David Howells <dhowells@redhat.com>
Fix the refcounting of the authentication keys in the file locking code.
The vnode->lock_key member points to a key on which it expects to be
holding a ref, but it isn't always given an extra ref, however.
Fixes: 0fafdc9f88 ("afs: Fix file locking")
Signed-off-by: David Howells <dhowells@redhat.com>
A cb_interest record is not necessarily attached to the vnode on entry to
afs_validate(), which can cause an oops when we try to bring the vnode's
cb_s_break up to date in the default case (ie. no current callback promise
and the vnode has not been deleted).
Fix this by simply removing the line, as vnode->cb_s_break will be set when
needed by afs_register_server_cb_interest() when we next get a callback
promise from RPC call.
The oops looks something like:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
...
RIP: 0010:afs_validate+0x66/0x250 [kafs]
...
Call Trace:
afs_d_revalidate+0x8d/0x340 [kafs]
? __d_lookup+0x61/0x150
lookup_dcache+0x44/0x70
? lookup_dcache+0x44/0x70
__lookup_hash+0x24/0xa0
do_unlinkat+0x11d/0x2c0
__x64_sys_unlink+0x23/0x30
do_syscall_64+0x4d/0xf0
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: ae3b7361dc ("afs: Fix validation/callback interaction")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Commit c3ff2a5193 ("powerpc/32: add stack protector support")
caused kernel panic on PowerPC when an external module is used with
CONFIG_STACKPROTECTOR because the 'prepare' target was not executed
for the external module build.
Commit e07db28eea ("kbuild: fix single target build for external
module") turned it into a build error because the 'prepare' target is
now executed but the 'prepare0' target is missing for the external
module build.
External module on arm/arm64 with CONFIG_STACKPROTECTOR_PER_TASK is
also broken in the same way.
Move 'PHONY += prepare0' to the common place. GNU Make is fine with
missing rule for phony targets. I also removed the comment which is
wrong irrespective of this commit.
I minimize the change so it can be easily backported to 4.20.x
To fix v4.20, please backport e07db28eea ("kbuild: fix single target
build for external module"), and then this commit.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201891
Fixes: e07db28eea ("kbuild: fix single target build for external module")
Fixes: c3ff2a5193 ("powerpc/32: add stack protector support")
Fixes: 189af46571 ("ARM: smp: add support for per-task stack canaries")
Fixes: 0a1213fa74 ("arm64: enable per-task stack canaries")
Cc: linux-stable <stable@vger.kernel.org> # v4.20
Reported-by: Samuel Holland <samuel@sholland.org>
Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
- LDFLAGS_vmlinux is cleared by the top Makefile
- 'all: vmlinux' is specified by the top Makefile
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
- scripts/Kbuild.include already defined 'comma'
- The top Makefile has 'PHONY += FORCE'
- include/asm-*/ was moved to arch/*/include/asm/ a decade ago
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Pull security subsystem fixes from James Morris:
"Fixes for the security subsystem.
The first (by Casey actually - it's misattributed) fixes a regression
introduced with the LSM stacking changes"
* 'fixes-v5.0-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
LSM: Check for NULL cred-security on free
Yama: Check for pid death before checking ancestry
seccomp: fix UAF in user-trap code
[Why]
Backlight is conceptually a property of links, not streams.
All backlight programming is done on links, but there is a
stream property bl_pwm_level that is used to restore backlight
on dpms on and s3 resume. This is unnecessary, as backlight
is already restored by hardware with no driver intervention.
[How]
Remove bl_pwm_level, and the stream argument to set_backlight
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=109375
Signed-off-by: David Francis <David.Francis@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Acked-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 923fe49512)
Prateek Sood
Linus Torvalds
Dave Airlie
Kangjie Lu
Cheng-Min Ao
David Howells
Marc Dionne
Masahiro Yamada
Jani Nikula
James Morris
David Francis