While debugging the rtmutex unlock vs. dequeue race Will suggested to use
READ_ONCE() in rt_mutex_owner() as it might race against the
cmpxchg_release() in unlock_rt_mutex_safe().
Will: "It's a minor thing which will most likely not matter in practice"
Careful search did not unearth an actual problem in todays code, but it's
better to be safe than surprised.
Suggested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20161130210030.431379999@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
David reported a futex/rtmutex state corruption. It's caused by the
following problem:
CPU0 CPU1 CPU2
l->owner=T1
rt_mutex_lock(l)
lock(l->wait_lock)
l->owner = T1 | HAS_WAITERS;
enqueue(T2)
boost()
unlock(l->wait_lock)
schedule()
rt_mutex_lock(l)
lock(l->wait_lock)
l->owner = T1 | HAS_WAITERS;
enqueue(T3)
boost()
unlock(l->wait_lock)
schedule()
signal(->T2) signal(->T3)
lock(l->wait_lock)
dequeue(T2)
deboost()
unlock(l->wait_lock)
lock(l->wait_lock)
dequeue(T3)
===> wait list is now empty
deboost()
unlock(l->wait_lock)
lock(l->wait_lock)
fixup_rt_mutex_waiters()
if (wait_list_empty(l)) {
owner = l->owner & ~HAS_WAITERS;
l->owner = owner
==> l->owner = T1
}
lock(l->wait_lock)
rt_mutex_unlock(l) fixup_rt_mutex_waiters()
if (wait_list_empty(l)) {
owner = l->owner & ~HAS_WAITERS;
cmpxchg(l->owner, T1, NULL)
===> Success (l->owner = NULL)
l->owner = owner
==> l->owner = T1
}
That means the problem is caused by fixup_rt_mutex_waiters() which does the
RMW to clear the waiters bit unconditionally when there are no waiters in
the rtmutexes rbtree.
This can be fatal: A concurrent unlock can release the rtmutex in the
fastpath because the waiters bit is not set. If the cmpxchg() gets in the
middle of the RMW operation then the previous owner, which just unlocked
the rtmutex is set as the owner again when the write takes place after the
successfull cmpxchg().
The solution is rather trivial: verify that the owner member of the rtmutex
has the waiters bit set before clearing it. This does not require a
cmpxchg() or other atomic operations because the waiters bit can only be
set and cleared with the rtmutex wait_lock held. It's also safe against the
fast path unlock attempt. The unlock attempt via cmpxchg() will either see
the bit set and take the slowpath or see the bit cleared and release it
atomically in the fastpath.
It's remarkable that the test program provided by David triggers on ARM64
and MIPS64 really quick, but it refuses to reproduce on x86-64, while the
problem exists there as well. That refusal might explain that this got not
discovered earlier despite the bug existing from day one of the rtmutex
implementation more than 10 years ago.
Thanks to David for meticulously instrumenting the code and providing the
information which allowed to decode this subtle problem.
Reported-by: David Daney <ddaney@caviumnetworks.com>
Tested-by: David Daney <david.daney@cavium.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: stable@vger.kernel.org
Fixes: 23f78d4a03 ("[PATCH] pi-futex: rt mutex core")
Link: http://lkml.kernel.org/r/20161130210030.351136722@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since the KERN_CONT changes the locking-selftest output is messed up, eg:
----------------------------------------------------------------------------
| spin |wlock |rlock |mutex | wsem | rsem |
--------------------------------------------------------------------------
A-A deadlock:
ok |
ok |
ok |
ok |
ok |
ok |
Use pr_cont() to get it looking normal again:
----------------------------------------------------------------------------
| spin |wlock |rlock |mutex | wsem | rsem |
--------------------------------------------------------------------------
A-A deadlock: ok | ok | ok | ok | ok | ok |
Reported-by: Christian Kujau <lists@nerdbynature.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/1480027528-934-1-git-send-email-mpe@ellerman.id.au
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Stable Bugfixes:
- Hide array-bounds warning
Bugfixes:
- Keep a reference on lock states while checking
- Handle NFS4ERR_OLD_STATEID in nfs4_reclaim_open_state
- Don't call close if the open stateid has already been cleared
- Fix CLOSE rases with OPEN
- Fix a regression in DELEGRETURN
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Merge tag 'nfs-for-4.9-4' of git://git.linux-nfs.org/projects/anna/linux-nfs
Pull NFS client bugfixes from Anna Schumaker:
"Most of these fix regressions or races, but there is one patch for
stable that Arnd sent me
Stable bugfix:
- Hide array-bounds warning
Bugfixes:
- Keep a reference on lock states while checking
- Handle NFS4ERR_OLD_STATEID in nfs4_reclaim_open_state
- Don't call close if the open stateid has already been cleared
- Fix CLOSE rases with OPEN
- Fix a regression in DELEGRETURN"
* tag 'nfs-for-4.9-4' of git://git.linux-nfs.org/projects/anna/linux-nfs:
NFSv4.x: hide array-bounds warning
NFSv4.1: Keep a reference on lock states while checking
NFSv4.1: Handle NFS4ERR_OLD_STATEID in nfs4_reclaim_open_state
NFSv4: Don't call close if the open stateid has already been cleared
NFSv4: Fix CLOSE races with OPEN
NFSv4.1: Fix a regression in DELEGRETURN
Pull arch/tile bugfix from Chris Metcalf:
"This fixes a bug that causes reboots after 208 days of uptime :-)"
* 'stable' of git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
tile: avoid using clocksource_cyc2ns with absolute cycle count
For large values of "mult" and long uptimes, the intermediate
result of "cycles * mult" can overflow 64 bits. For example,
the tile platform calls clocksource_cyc2ns with a 1.2 GHz clock;
we have mult = 853, and after 208.5 days, we overflow 64 bits.
Since clocksource_cyc2ns() is intended to be used for relative
cycle counts, not absolute cycle counts, performance is more
importance than accepting a wider range of cycle values. So,
just use mult_frac() directly in tile's sched_clock().
Commit 4cecf6d401 ("sched, x86: Avoid unnecessary overflow
in sched_clock") by Salman Qazi results in essentially the same
generated code for x86 as this change does for tile. In fact,
a follow-on change by Salman introduced mult_frac() and switched
to using it, so the C code was largely identical at that point too.
Peter Zijlstra then added mul_u64_u32_shr() and switched x86
to use it. This is, in principle, better; by optimizing the
64x64->64 multiplies to be 32x32->64 multiplies we can potentially
save some time. However, the compiler piplines the 64x64->64
multiplies pretty well, and the conditional branch in the generic
mul_u64_u32_shr() causes some bubbles in execution, with the
result that it's pretty much a wash. If tilegx provided its own
implementation of mul_u64_u32_shr() without the conditional branch,
we could potentially save 3 cycles, but that seems like small gain
for a fair amount of additional build scaffolding; no other platform
currently provides a mul_u64_u32_shr() override, and tile doesn't
currently have an <asm/div64.h> header to put the override in.
Additionally, gcc currently has an optimization bug that prevents
it from recognizing the opportunity to use a 32x32->64 multiply,
and so the result would be no better than the existing mult_frac()
until such time as the compiler is fixed.
For now, just using mult_frac() seems like the right answer.
Cc: stable@kernel.org [v3.4+]
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Pull perf fixes from Ingo Molnar:
"Six fixes for bugs that were found via fuzzing, and a trivial
hw-enablement patch for AMD Family-17h CPU PMUs"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/uncore: Allow only a single PMU/box within an events group
perf/x86/intel: Cure bogus unwind from PEBS entries
perf/x86: Restore TASK_SIZE check on frame pointer
perf/core: Fix address filter parser
perf/x86: Add perf support for AMD family-17h processors
perf/x86/uncore: Fix crash by removing bogus event_list[] handling for SNB client uncore IMC
perf/core: Do not set cpuctx->cgrp for unscheduled cgroups
Pull crypto fixes from Herbert Xu:
"The last push broke algif_hash for all shash implementations, so this
is a follow-up to fix that.
This also fixes a problem in the crypto scatterwalk that triggers a
BUG_ON with certain debugging options due to the new vmalloced-stack
code"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: scatterwalk - Remove unnecessary aliasing check in map_and_copy
crypto: algif_hash - Fix result clobbering in recvmsg
Pull thermal management fix from Zhang Rui:
"We only have one urgent fix this time.
Commit 3105f234e0 ("thermal/powerclamp: correct cpu support check"),
which is shipped in 4.9-rc3, fixed a problem introduced by commit
b721ca0d19 ("thermal/powerclamp: remove cpu whitelist").
But unfortunately, it broke intel_powerclamp driver module auto-
loading at the same time. Thus we need this change to add back module
auto-loading for 4.9"
* 'for-rc' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
thermal/powerclamp: add back module device table
Two small fixes. One prevents timeouts on mpt3sas when trying to use
the secure erase protocol which causes the erase protocol to be
aborted. The second is a regression in a prior fix which causes all
commands to abort during PCI extended error recovery, which is
incorrect because PCI EEH is independent from what's happening on the
FC transport.
Signed-off-by: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
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Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"Two small fixes.
One prevents timeouts on mpt3sas when trying to use the secure erase
protocol which causes the erase protocol to be aborted. The second is
a regression in a prior fix which causes all commands to abort during
PCI extended error recovery, which is incorrect because PCI EEH is
independent from what's happening on the FC transport"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: qla2xxx: do not abort all commands in the adapter during EEH recovery
scsi: mpt3sas: Fix secure erase premature termination
configuration and a bad frequency calculation. The other two are fixes for
passing the wrong pointer in drivers recently converted to clk_hw style
registration.
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Merge tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk fixes from Stephen Boyd:
"A handful of driver fixes.
The sunxi fixes are for an incorrect clk tree configuration and a bad
frequency calculation. The other two are fixes for passing the wrong
pointer in drivers recently converted to clk_hw style registration"
* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
clk: efm32gg: Pass correct type to hw provider registration
clk: berlin: Pass correct type to hw provider registration
clk: sunxi: Fix M factor computation for APB1
clk: sunxi-ng: sun6i-a31: Force AHB1 clock to use PLL6 as parent
A correct bugfix introduced a harmless warning that shows up with gcc-7:
fs/nfs/callback.c: In function 'nfs_callback_up':
fs/nfs/callback.c:214:14: error: array subscript is outside array bounds [-Werror=array-bounds]
What happens here is that the 'minorversion == 0' check tells the
compiler that we assume minorversion can be something other than 0,
but when CONFIG_NFS_V4_1 is disabled that would be invalid and
result in an out-of-bounds access.
The added check for IS_ENABLED(CONFIG_NFS_V4_1) tells gcc that this
really can't happen, which makes the code slightly smaller and also
avoids the warning.
The bugfix that introduced the warning is marked for stable backports,
we want this one backported to the same releases.
Fixes: 98b0f80c23 ("NFSv4.x: Fix a refcount leak in nfs_callback_up_net")
Cc: stable@vger.kernel.org # v3.7+
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Pull scheduler fixes from Ingo Molnar:
"Two fixes for autogroup scheduling, for races when turning the feature
on/off via /proc/sys/kernel/sched_autogroup_enabled"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/autogroup: Do not use autogroup->tg in zombie threads
sched/autogroup: Fix autogroup_move_group() to never skip sched_move_task()
Pull x86 fixes from Ingo Molnar:
"Misc fixes:
- two fixes to make (very) old Intel CPUs boot reliably
- fix the intel-mid driver and rename it
- two KASAN false positive fixes
- an FPU fix
- two sysfb fixes
- two build fixes related to new toolchain versions"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/intel-mid: Rename platform_wdt to platform_mrfld_wdt
x86/build: Build compressed x86 kernels as PIE when !CONFIG_RELOCATABLE as well
x86/platform/intel-mid: Register watchdog device after SCU
x86/fpu: Fix invalid FPU ptrace state after execve()
x86/boot: Fail the boot if !M486 and CPUID is missing
x86/traps: Ignore high word of regs->cs in early_fixup_exception()
x86/dumpstack: Prevent KASAN false positive warnings
x86/unwind: Prevent KASAN false positive warnings in guess unwinder
x86/boot: Avoid warning for zero-filling .bss
x86/sysfb: Fix lfb_size calculation
x86/sysfb: Add support for 64bit EFI lfb_base
An over-committed guest with more vCPUs than pCPUs has a heavy overload
in osq_lock().
This is because if vCPU-A holds the osq lock and yields out, vCPU-B ends
up waiting for per_cpu node->locked to be set. IOW, vCPU-B waits for
vCPU-A to run and unlock the osq lock.
Use the new vcpu_is_preempted(cpu) interface to detect if a vCPU is
currently running or not, and break out of the spin-loop if so.
test case:
$ perf record -a perf bench sched messaging -g 400 -p && perf report
before patch:
18.09% sched-messaging [kernel.vmlinux] [k] osq_lock
12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
5.27% sched-messaging [kernel.vmlinux] [k] mutex_unlock
3.89% sched-messaging [kernel.vmlinux] [k] wait_consider_task
3.64% sched-messaging [kernel.vmlinux] [k] _raw_write_lock_irq
3.41% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner.is
2.49% sched-messaging [kernel.vmlinux] [k] system_call
after patch:
20.68% sched-messaging [kernel.vmlinux] [k] mutex_spin_on_owner
8.45% sched-messaging [kernel.vmlinux] [k] mutex_unlock
4.12% sched-messaging [kernel.vmlinux] [k] system_call
3.01% sched-messaging [kernel.vmlinux] [k] system_call_common
2.83% sched-messaging [kernel.vmlinux] [k] copypage_power7
2.64% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner
2.00% sched-messaging [kernel.vmlinux] [k] osq_lock
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: linuxppc-dev@lists.ozlabs.org
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: rkrcmar@redhat.com
Cc: virtualization@lists.linux-foundation.org
Cc: will.deacon@arm.com
Cc: xen-devel-request@lists.xenproject.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1478077718-37424-3-git-send-email-xinhui.pan@linux.vnet.ibm.com
[ Translated to English. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Group validation expects all events to be of the same PMU; however
is_uncore_pmu() is too wide, it matches _all_ uncore events, even
across PMUs.
This triggers failure when we group different events from different
uncore PMUs, like:
perf stat -vv -e '{uncore_cbox_0/config=0x0334/,uncore_qpi_0/event=1/}' -a sleep 1
Fix is_uncore_pmu() by only matching events to the box at hand.
Note that generic code; ran after this step; will disallow this
mixture of PMU events.
Reported-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vince@deater.net>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/20161118125354.GQ3117@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Vince Weaver reported that perf_fuzzer + KASAN detects that PEBS event
unwinds sometimes do 'weird' things. In particular, we seemed to be
ending up unwinding from random places on the NMI stack.
While it was somewhat expected that the event record BP,SP would not
match the interrupt BP,SP in that the interrupt is strictly later than
the record event, it was overlooked that it could be on an already
overwritten stack.
Therefore, don't copy the recorded BP,SP over the interrupted BP,SP
when we need stack unwinds.
Note that its still possible the unwind doesn't full match the actual
event, as its entirely possible to have done an (I)RET between record
and interrupt, but on average it should still point in the general
direction of where the event came from. Also, it's the best we can do,
considering.
The particular scenario that triggered the bogus NMI stack unwind was
a PEBS event with very short period, upon enabling the event at the
tail of the PMI handler (FREEZE_ON_PMI is not used), it instantly
triggers a record (while still on the NMI stack) which in turn
triggers the next PMI. This then causes back-to-back NMIs and we'll
try and unwind the stack-frame from the last NMI, which obviously is
now overwritten by our own.
Analyzed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: davej@codemonkey.org.uk <davej@codemonkey.org.uk>
Cc: dvyukov@google.com <dvyukov@google.com>
Cc: stable@vger.kernel.org
Fixes: ca037701a0 ("perf, x86: Add PEBS infrastructure")
Link: http://lkml.kernel.org/r/20161117171731.GV3157@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The following commit:
75925e1ad7 ("perf/x86: Optimize stack walk user accesses")
... switched from copy_from_user_nmi() to __copy_from_user_nmi() with a manual
access_ok() check.
Unfortunately, copy_from_user_nmi() does an explicit check against TASK_SIZE,
whereas the access_ok() uses whatever the current address limit of the task is.
We are getting NMIs when __probe_kernel_read() has switched to KERNEL_DS, and
then see vmalloc faults when we access what looks like pointers into vmalloc
space:
[] WARNING: CPU: 3 PID: 3685731 at arch/x86/mm/fault.c:435 vmalloc_fault+0x289/0x290
[] CPU: 3 PID: 3685731 Comm: sh Tainted: G W 4.6.0-5_fbk1_223_gdbf0f40 #1
[] Call Trace:
[] <NMI> [<ffffffff814717d1>] dump_stack+0x4d/0x6c
[] [<ffffffff81076e43>] __warn+0xd3/0xf0
[] [<ffffffff81076f2d>] warn_slowpath_null+0x1d/0x20
[] [<ffffffff8104a899>] vmalloc_fault+0x289/0x290
[] [<ffffffff8104b5a0>] __do_page_fault+0x330/0x490
[] [<ffffffff8104b70c>] do_page_fault+0xc/0x10
[] [<ffffffff81794e82>] page_fault+0x22/0x30
[] [<ffffffff81006280>] ? perf_callchain_user+0x100/0x2a0
[] [<ffffffff8115124f>] get_perf_callchain+0x17f/0x190
[] [<ffffffff811512c7>] perf_callchain+0x67/0x80
[] [<ffffffff8114e750>] perf_prepare_sample+0x2a0/0x370
[] [<ffffffff8114e840>] perf_event_output+0x20/0x60
[] [<ffffffff8114aee7>] ? perf_event_update_userpage+0xc7/0x130
[] [<ffffffff8114ea01>] __perf_event_overflow+0x181/0x1d0
[] [<ffffffff8114f484>] perf_event_overflow+0x14/0x20
[] [<ffffffff8100a6e3>] intel_pmu_handle_irq+0x1d3/0x490
[] [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
[] [<ffffffff81197191>] ? vunmap_page_range+0x1a1/0x2f0
[] [<ffffffff811972f1>] ? unmap_kernel_range_noflush+0x11/0x20
[] [<ffffffff814f2056>] ? ghes_copy_tofrom_phys+0x116/0x1f0
[] [<ffffffff81040d1d>] ? x2apic_send_IPI_self+0x1d/0x20
[] [<ffffffff8100411d>] perf_event_nmi_handler+0x2d/0x50
[] [<ffffffff8101ea31>] nmi_handle+0x61/0x110
[] [<ffffffff8101ef94>] default_do_nmi+0x44/0x110
[] [<ffffffff8101f13b>] do_nmi+0xdb/0x150
[] [<ffffffff81795187>] end_repeat_nmi+0x1a/0x1e
[] [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
[] [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
[] [<ffffffff8147daf7>] ? copy_user_enhanced_fast_string+0x7/0x10
[] <<EOE>> <IRQ> [<ffffffff8115d05e>] ? __probe_kernel_read+0x3e/0xa0
Fix this by moving the valid_user_frame() check to before the uaccess
that loads the return address and the pointer to the next frame.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Fixes: 75925e1ad7 ("perf/x86: Optimize stack walk user accesses")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Exactly because for_each_thread() in autogroup_move_group() can't see it
and update its ->sched_task_group before _put() and possibly free().
So the exiting task needs another sched_move_task() before exit_notify()
and we need to re-introduce the PF_EXITING (or similar) check removed by
the previous change for another reason.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hartsjc@redhat.com
Cc: vbendel@redhat.com
Cc: vlovejoy@redhat.com
Link: http://lkml.kernel.org/r/20161114184612.GA15968@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The PF_EXITING check in task_wants_autogroup() is no longer needed. Remove
it, but see the next patch.
However the comment is correct in that autogroup_move_group() must always
change task_group() for every thread so the sysctl_ check is very wrong;
we can race with cgroups and even sys_setsid() is not safe because a task
running with task_group() == ag->tg must participate in refcounting:
int main(void)
{
int sctl = open("/proc/sys/kernel/sched_autogroup_enabled", O_WRONLY);
assert(sctl > 0);
if (fork()) {
wait(NULL); // destroy the child's ag/tg
pause();
}
assert(pwrite(sctl, "1\n", 2, 0) == 2);
assert(setsid() > 0);
if (fork())
pause();
kill(getppid(), SIGKILL);
sleep(1);
// The child has gone, the grandchild runs with kref == 1
assert(pwrite(sctl, "0\n", 2, 0) == 2);
assert(setsid() > 0);
// runs with the freed ag/tg
for (;;)
sleep(1);
return 0;
}
crashes the kernel. It doesn't really need sleep(1), it doesn't matter if
autogroup_move_group() actually frees the task_group or this happens later.
Reported-by: Vern Lovejoy <vlovejoy@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hartsjc@redhat.com
Cc: vbendel@redhat.com
Link: http://lkml.kernel.org/r/20161114184609.GA15965@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The aliasing check in map_and_copy is no longer necessary because
the IPsec ESP code no longer provides an IV that points into the
actual request data. As this check is now triggering BUG checks
due to the vmalloced stack code, I'm removing it.
Reported-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Recently an init call was added to hash_recvmsg so as to reset
the hash state in case a sendmsg call was never made.
Unfortunately this ended up clobbering the result if the previous
sendmsg was done with a MSG_MORE flag. This patch fixes it by
excluding that case when we make the init call.
Fixes: a8348bca29 ("algif_hash - Fix NULL hash crash with shash")
Reported-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull apparmor bugfix from James Morris:
"This has a fix for a policy replacement bug that is fairly serious for
apache mod_apparmor users, as it results in the wrong policy being
applied on an network facing service"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
apparmor: fix change_hat not finding hat after policy replacement
Pull sparc fixes from David Miller:
1) With modern networking cards we can run out of 32-bit DMA space, so
support 64-bit DMA addressing when possible on sparc64. From Dave
Tushar.
2) Some signal frame validation checks are inverted on sparc32, fix
from Andreas Larsson.
3) Lockdep tables can get too large in some circumstances on sparc64,
add a way to adjust the size a bit. From Babu Moger.
4) Fix NUMA node probing on some sun4v systems, from Thomas Tai.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
sparc: drop duplicate header scatterlist.h
lockdep: Limit static allocations if PROVE_LOCKING_SMALL is defined
config: Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc
sunbmac: Fix compiler warning
sunqe: Fix compiler warnings
sparc64: Enable 64-bit DMA
sparc64: Enable sun4v dma ops to use IOMMU v2 APIs
sparc64: Bind PCIe devices to use IOMMU v2 service
sparc64: Initialize iommu_map_table and iommu_pool
sparc64: Add ATU (new IOMMU) support
sparc64: Add FORCE_MAX_ZONEORDER and default to 13
sparc64: fix compile warning section mismatch in find_node()
sparc32: Fix inverted invalid_frame_pointer checks on sigreturns
sparc64: Fix find_node warning if numa node cannot be found
Pull networking fixes from David Miller:
1) Clear congestion control state when changing algorithms on an
existing socket, from Florian Westphal.
2) Fix register bit values in altr_tse_pcs portion of stmmac driver,
from Jia Jie Ho.
3) Fix PTP handling in stammc driver for GMAC4, from Giuseppe
CAVALLARO.
4) Fix udplite multicast delivery handling, it ignores the udp_table
parameter passed into the lookups, from Pablo Neira Ayuso.
5) Synchronize the space estimated by rtnl_vfinfo_size and the space
actually used by rtnl_fill_vfinfo. From Sabrina Dubroca.
6) Fix memory leak in fib_info when splitting nodes, from Alexander
Duyck.
7) If a driver does a napi_hash_del() explicitily and not via
netif_napi_del(), it must perform RCU synchronization as needed. Fix
this in virtio-net and bnxt drivers, from Eric Dumazet.
8) Likewise, it is not necessary to invoke napi_hash_del() is we are
also doing neif_napi_del() in the same code path. Remove such calls
from be2net and cxgb4 drivers, also from Eric Dumazet.
9) Don't allocate an ID in peernet2id_alloc() if the netns is dead,
from WANG Cong.
10) Fix OF node and device struct leaks in of_mdio, from Johan Hovold.
11) We cannot cache routes in ip6_tunnel when using inherited traffic
classes, from Paolo Abeni.
12) Fix several crashes and leaks in cpsw driver, from Johan Hovold.
13) Splice operations cannot use freezable blocking calls in AF_UNIX,
from WANG Cong.
14) Link dump filtering by master device and kind support added an error
in loop index updates during the dump if we actually do filter, fix
from Zhang Shengju.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (59 commits)
tcp: zero ca_priv area when switching cc algorithms
net: l2tp: Treat NET_XMIT_CN as success in l2tp_eth_dev_xmit
ethernet: stmmac: make DWMAC_STM32 depend on it's associated SoC
tipc: eliminate obsolete socket locking policy description
rtnl: fix the loop index update error in rtnl_dump_ifinfo()
l2tp: fix racy SOCK_ZAPPED flag check in l2tp_ip{,6}_bind()
net: macb: add check for dma mapping error in start_xmit()
rtnetlink: fix FDB size computation
netns: fix get_net_ns_by_fd(int pid) typo
af_unix: conditionally use freezable blocking calls in read
net: ethernet: ti: cpsw: fix fixed-link phy probe deferral
net: ethernet: ti: cpsw: add missing sanity check
net: ethernet: ti: cpsw: fix secondary-emac probe error path
net: ethernet: ti: cpsw: fix of_node and phydev leaks
net: ethernet: ti: cpsw: fix deferred probe
net: ethernet: ti: cpsw: fix mdio device reference leak
net: ethernet: ti: cpsw: fix bad register access in probe error path
net: sky2: Fix shutdown crash
cfg80211: limit scan results cache size
net sched filters: pass netlink message flags in event notification
...
We need to zero out the private data area when application switches
connection to different algorithm (TCP_CONGESTION setsockopt).
When congestion ops get assigned at connect time everything is already
zeroed because sk_alloc uses GFP_ZERO flag. But in the setsockopt case
this contains whatever previous cc placed there.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
The tc could return NET_XMIT_CN as one congestion notification, but
it does not mean the packe is lost. Other modules like ipvlan,
macvlan, and others treat NET_XMIT_CN as success too.
So l2tp_eth_dev_xmit should add the NET_XMIT_CN check.
Signed-off-by: Gao Feng <gfree.wind@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While walking the list of lock_states, keep a reference on each
nfs4_lock_state to be checked, otherwise the lock state could be removed
while the check performs TEST_STATEID and possible FREE_STATEID.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
There's not much point, except compile test, enabling the stmmac
platform drivers unless the STM32 SoC is enabled. It's not
useful without it.
Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 3105f234e0 replaced module
cpu id table with a cpu feature check, which is logically correct.
But we need the module device table to allow module auto loading.
Cc: stable@vger.kernel.org # 4.8
Fixes:3105f234 thermal/powerclamp: correct cpu support check
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
The token table passed into match_token() must be null-terminated, which
it currently is not in the perf's address filter string parser, as caught
by Vince's perf_fuzzer and KASAN.
It doesn't blow up otherwise because of the alignment padding of the table
to the next element in the .rodata, which is luck.
Fixing by adding a null-terminator to the token table.
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dvyukov@google.com
Cc: stable@vger.kernel.org # v4.7+
Fixes: 375637bc52 ("perf/core: Introduce address range filtering")
Link: http://lkml.kernel.org/r/877f81f264.fsf@ashishki-desk.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rename the watchdog platform library file to explicitly show that is used only
on Intel Merrifield platforms.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161118172723.179761-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Since the bootloader may load the compressed x86 kernel at any address,
it should always be built as PIE, not just when CONFIG_RELOCATABLE=y.
Otherwise, linker in binutils 2.27 will optimize GOT load into the
absolute address when building the compressed x86 kernel as a non-PIE
executable.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
[ Small wording changes. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Watchdog device in Intel Tangier relies on SCU to be present. It uses the SCU
IPC channel to send commands and receive responses. If watchdog driver is
initialized quite before SCU and a command has been sent the result is always
an error like the following:
intel_mid_wdt: Error stopping watchdog: 0xffffffed
Register watchdog device whne SCU is ready to avoid described issue.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161118165224.175514-1-andriy.shevchenko@linux.intel.com
[ Small cleanups. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Robert O'Callahan reported that after an execve PTRACE_GETREGSET
NT_X86_XSTATE continues to return the pre-exec register values
until the exec'ed task modifies FPU state.
The test code is at:
https://bugzilla.redhat.com/attachment.cgi?id=1164286.
What is happening is fpu__clear() does not properly clear fpstate.
Fix it by doing just that.
Reported-by: Robert O'Callahan <robert@ocallahan.org>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Cc: <stable@vger.kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1479402695-6553-1-git-send-email-yu-cheng.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Currently the wake_q data structure is defined by the WAKE_Q() macro.
This macro, however, looks like a function doing something as "wake" is
a verb. Even checkpatch.pl was confused as it reported warnings like
WARNING: Missing a blank line after declarations
#548: FILE: kernel/futex.c:3665:
+ int ret;
+ WAKE_Q(wake_q);
This patch renames the WAKE_Q() macro to DEFINE_WAKE_Q() which clarifies
what the macro is doing and eliminates the checkpatch.pl warnings.
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1479401198-1765-1-git-send-email-longman@redhat.com
[ Resolved conflict and added missing rename. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Linux will have all kinds of sporadic problems on systems that don't
have the CPUID instruction unless CONFIG_M486=y. In particular,
sync_core() will explode.
I believe that these kernels had a better chance of working before
commit 05fb3c199b ("x86/boot: Initialize FPU and X86_FEATURE_ALWAYS
even if we don't have CPUID"). That commit inadvertently fixed a
serious bug: we used to fail to detect the FPU if CPUID wasn't
present. Because we also used to forget to set X86_FEATURE_ALWAYS, we
end up with no cpu feature bits set at all. This meant that
alternative patching didn't do anything and, if paravirt was disabled,
we could plausibly finish the entire boot process without calling
sync_core().
Rather than trying to work around these issues, just have the kernel
fail loudly if it's running on a CPUID-less 486, doesn't have CPUID,
and doesn't have CONFIG_M486 set.
Reported-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/70eac6639f23df8be5fe03fa1984aedd5d40077a.1479598603.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
