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Ingo rightfully asked for a bit more documentation in the nolibc header,
so this patch adds some explanation about its purpose, how it's made, and
how to use it.
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
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A few macros had their rightmost backslash misaligned, and the pollfd
struct definition resisted the previous code reindent. Nothing else
changed.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
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A last-minute checkpatch cleanup caused most of list of clobbered
registers to be lost in the MIPS syscall definition. Although this code
is not yet used on MIPS, it is nevertheless better to fix it before it
does get used.
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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The ever-evolving IS_ENABLED() macro is intended for CONFIG_* Kconfig
options, but rcuperf currently uses it for the decidedly non-CONFIG_*
MODULE macro. In the spirit of not inviting trouble, this commit
substitutes tried-and-true #ifdef.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
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Beyond a certain point in the CPU-hotplug offline process, timers get
stranded on the outgoing CPU, and won't fire until that CPU comes back
online, which might well be never. This commit therefore adds a hook
in torture_onoff_init() that is invoked from torture_offline(), which
rcutorture uses to occasionally wait for a grace period. This should
result in failures for RCU implementations that rely on stranded timers
eventually firing in the absence of the CPU coming back online.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Why a Bourne-shell "for" loop? And why 192 instances of "a"? This commit
adds a shell comment to present the answer to these mysteries. It also
uses a series of factor-of-four Bourne-shell assignments to make it
easy to see how many instances there are, replacing the earlier wall of
'a' characters.
Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
[ paulmck: Fix wrong-variable bugs noted by Andrea Parri. ]
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This commit records grace periods in rcutorture's n_launders_hist[]
histogram, thus allowing rcu_torture_fwd_cb_hist() to print out the
elapsed number of grace periods between buckets. This information
helps to determine whether a lack of forward progress is due to stalled
grace periods on the one hand or due to sluggish callback invocation on
the other.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Currently, __note_gp_changes() checks to see if the rcu_node structure's
->gp_seq_needed is greater than or equal to that of the rcu_data
structure, and if so, updates the rcu_data structure's ->gp_seq_needed
field. This results in a useless store in the case where the two fields
are equal.
This commit therefore carries out this store only in the case where the
rcu_node structure's ->gp_seq_needed is strictly greater than that of
the rcu_data structure.
Signed-off-by: "Zhang, Jun" <jun.zhang@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Link: https://lkml.kernel.org/r/88DC34334CA3444C85D647DBFA962C2735AD5F77@SHSMSX104.ccr.corp.intel.com
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The rcu_gp_kthread_wake() function is invoked when it might be necessary
to wake the RCU grace-period kthread. Because self-wakeups are normally
a useless waste of CPU cycles, if rcu_gp_kthread_wake() is invoked from
this kthread, it naturally refuses to do the wakeup.
Unfortunately, natural though it might be, this heuristic fails when
rcu_gp_kthread_wake() is invoked from an interrupt or softirq handler
that interrupted the grace-period kthread just after the final check of
the wait-event condition but just before the schedule() call. In this
case, a wakeup is required, even though the call to rcu_gp_kthread_wake()
is within the RCU grace-period kthread's context. Failing to provide
this wakeup can result in grace periods failing to start, which in turn
results in out-of-memory conditions.
This race window is quite narrow, but it actually did happen during real
testing. It would of course need to be fixed even if it was strictly
theoretical in nature.
This patch does not Cc stable because it does not apply cleanly to
earlier kernel versions.
Fixes: 48a7639ce80c ("rcu: Make callers awaken grace-period kthread")
Reported-by: "He, Bo" <bo.he@intel.com>
Co-developed-by: "Zhang, Jun" <jun.zhang@intel.com>
Co-developed-by: "He, Bo" <bo.he@intel.com>
Co-developed-by: "xiao, jin" <jin.xiao@intel.com>
Co-developed-by: Bai, Jie A <jie.a.bai@intel.com>
Signed-off: "Zhang, Jun" <jun.zhang@intel.com>
Signed-off: "He, Bo" <bo.he@intel.com>
Signed-off: "xiao, jin" <jin.xiao@intel.com>
Signed-off: Bai, Jie A <jie.a.bai@intel.com>
Signed-off-by: "Zhang, Jun" <jun.zhang@intel.com>
[ paulmck: Switch from !in_softirq() to "!in_interrupt() &&
!in_serving_softirq() to avoid redundant wakeups and to also handle the
interrupt-handler scenario as well as the softirq-handler scenario that
actually occurred in testing. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Link: https://lkml.kernel.org/r/CD6925E8781EFD4D8E11882D20FC406D52A11F61@SHSMSX104.ccr.corp.intel.com
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Life is hard if RCU manages to get stuck without triggering RCU CPU
stall warnings or triggering the rcu_check_gp_start_stall() checks
for failing to start a grace period. This commit therefore adds a
boot-time-selectable sysrq key (commandeering "y") that allows manually
dumping Tree RCU state. The new rcutree.sysrq_rcu kernel boot parameter
must be set for this sysrq to be available.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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The rcu_check_gp_kthread_starvation() function can be invoked without
holding locks, so the access to the rcu_state structure's ->gp_flags
field must be protected with READ_ONCE(). This commit therefore adds
this protection.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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If a grace period fails to start (for example, because you commented
out the last two lines of rcu_accelerate_cbs_unlocked()), rcu_core()
will invoke rcu_check_gp_start_stall(), which will notice and complain.
However, this complaint is lacking crucial debugging information such
as when the last wakeup executed and what the value of ->gp_seq was at
that time. This commit therefore removes the current pr_alert() from
rcu_check_gp_start_stall(), instead invoking show_rcu_gp_kthreads(),
which has been updated to print the needed information, which is collected
by rcu_gp_kthread_wake().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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This commit updates a few obsolete comments in the RCU callback-offload
code.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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The rcu_cpu_kthread_cpu used to provide debugfs information, but is no
longer used. This commit therefore removes it.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Given that RCU has a perfectly good per-CPU rcu_data structure, most
per-CPU quantities should be stored there.
This commit therefore moves the rcu_cpu_has_work per-CPU variable to
the rcu_data structure. This also makes this variable unconditionally
present, which should be acceptable given the memory reduction due to the
RCU flavor consolidation and also due to simplifications this will enable.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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The rcu_cpu_kthread_loops variable used to provide debugfs information,
but is no longer used. This commit therefore removes it.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Given that RCU has a perfectly good per-CPU rcu_data structure, most
per-CPU quantities should be stored there.
This commit therefore moves the rcu_cpu_kthread_status per-CPU variable
to the rcu_data structure. This also makes this variable unconditionally
present, which should be acceptable given the memory reduction due to the
RCU flavor consolidation and also due to simplifications this will enable.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Given that RCU has a perfectly good per-CPU rcu_data structure, most
per-CPU quantities should be stored there.
This commit therefore moves the rcu_cpu_kthread_task per-CPU variable to
the rcu_data structure. This also makes this variable unconditionally
present, which should be acceptable given the memory reduction due to the
RCU flavor consolidation and also due to simplifications this will enable.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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It is perfectly fine to set the rcutree.jiffies_till_first_fqs boot
parameter to zero, in fact, this can be useful on specialty systems that
usually have at least one idle CPU and that need fast grace periods.
This is because this setting causes the RCU grace-period kthread to
scan for idle threads immediately after grace-period initialization,
as opposed to waiting several jiffies to do so.
It is also perfectly fine to set the rcutree.rcu_kick_kthreads kernel
parameter, which gives the RCU grace-period kthread an extra wakeup
if it doesn't make progress for a period of three times the setting of
the rcutree.jiffies_till_first_fqs boot parameter. This is of course
problematic when the value of this parameter is zero, as it can result
in unnecessary wakeup IPIs along with unnecessary WARN_ONCE() invocations.
This commit therefore defers kthread kicking for at least two jiffies,
regardless of the setting of rcutree.jiffies_till_first_fqs.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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None of synchronize_rcu_bh, synchronize_rcu_bh_expedited, call_rcu_bh,
rcu_barrier_bh, synchronize_sched, synchronize_sched_expedited,
call_rcu_sched, rcu_barrier_sched, get_state_synchronize_sched, and
cond_synchronize_sched are actually used. This commit therefore removes
their trivial wrapper-function definitions.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Back when there were multiple flavors of RCU, it was necessary to
separately count lazy and non-lazy callbacks for each CPU. These counts
were used in CONFIG_RCU_FAST_NO_HZ kernels to determine how long a newly
idle CPU should be allowed to sleep before handling its RCU callbacks.
But now that there is only one flavor, the callback counts for a given
CPU's sole rcu_data structure are the counts for that CPU.
This commit therefore removes the rcu_data structure's ->nonlazy_posted
and ->nonlazy_posted_snap fields, the rcu_idle_count_callbacks_posted()
and rcu_cpu_has_callbacks() functions, repurposes the rcu_data structure's
->all_lazy field to record the laziness state at the beginning of the
latest idle sojourn, and modifies CONFIG_RCU_FAST_NO_HZ RCU CPU stall
warnings accordingly.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Now that _synchronize_rcu_expedited() has only one caller, and given that
this is a tail call, this commit inlines _synchronize_rcu_expedited()
into synchronize_rcu_expedited().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Now that rcu_blocking_is_gp() makes the correct immediate-return
decision for both PREEMPT and !PREEMPT, a single implementation of
synchronize_rcu() will work correctly under both configurations.
This commit therefore eliminates a few lines of code by consolidating
the two implementations of synchronize_rcu().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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The CONFIG_PREEMPT=n and CONFIG_PREEMPT=y implementations of
synchronize_rcu_expedited() are quite similar, and with small
modifications to rcu_blocking_is_gp() can be made identical. This commit
therefore makes this change in order to save a few lines of code and to
reduce the amount of duplicate code.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Back when there could be multiple RCU flavors running in the same kernel
at the same time, it was necessary to specify the expedited grace-period
IPI handler at runtime. Now that there is only one RCU flavor, the
IPI handler can be determined at build time. There is therefore no
longer any reason for the RCU-preempt and RCU-sched IPI handlers to
have different names, nor is there any reason to pass these handlers in
function arguments and in the data structures enclosing workqueues.
This commit therefore makes all these changes, pushing the specification
of the expedited grace-period IPI handler down to the point of use.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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The rcu_kthread_do_work() function has a single-line body and only one
remaining caller. This commit therefore saves a few lines of code by
inlining rcu_kthread_do_work() into its sole remaining caller.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Now that the RCU flavors have been consolidated, RCU_BH_FLAVOR and
RCU_SCHED_FLAVOR are no longer used. This commit therefore saves a
few lines by removing them.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Given that rcu_force_quiescent_state() is a simple wrapper around
force_quiescent_state(), this commit saves a few lines of code by
inlining force_quiescent_state() into rcu_force_quiescent_state(),
and changing all references to force_quiescent_state() to instead
invoke rcu_force_quiescent_state().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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During expedited RCU grace-period initialization, IPIs are sent to
all non-idle online CPUs. The IPI handler checks to see if the CPU is
in quiescent state, reporting one if so. This handler looks at three
different cases: (1) The CPU is not in an rcu_read_lock()-based critical
section, (2) The CPU is in the process of exiting an rcu_read_lock()-based
critical section, and (3) The CPU is in an rcu_read_lock()-based critical
section. In case (2), execution falls through into case (3).
This is harmless from a functionality viewpoint, but can result in
needless overhead during an improbable corner case. This commit therefore
adds the "return" statement needed to prevent fall-through.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Given RCU flavor consolidation, the name rcu_spawn_all_nocb_kthreads()
is quite misleading. It no longer ever creates more than one kthread,
and it does so only for the specified CPU. This commit therefore changes
this name to the more descriptive rcu_spawn_cpu_nocb_kthread(), and also
fixes up a similar issue in its header comment while in the area.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
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Now that synchronize_rcu() waits for preempt-disable regions of
code as well as RCU read-side critical sections, synchronize_sched()
can be replaced by synchronize_rcu(), in fact, synchronize_sched()
is now completely equivalent to synchronize_rcu(). This commit
therefore replaces synchronize_sched() with synchronize_rcu() so that
synchronize_sched() can eventually be removed entirely.
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
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Now that call_rcu()'s callback is not invoked until after all
preempt-disable regions of code have completed (in addition to explicitly
marked RCU read-side critical sections), call_rcu() can be used in place
of call_rcu_sched(). This commit therefore makes that change.
While in the area, this commit also updates an outdated header comment
for for_each_domain().
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
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The "--jobs" argument to the litmus-test scripts is similar to the "-jN"
argument to "make", so this commit allows the "-jN" form as well. While
in the area, it also prohibits the various forms of "-j0".
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20181203230451.28921-3-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The https://github.com/paulmckrcu/litmus repository contains a large
number of C-language litmus tests that include "Result:" comments
predicting the verification result. This commit adds a number of scripts
that run tests on these litmus tests:
checkghlitmus.sh:
Runs all litmus tests in the https://github.com/paulmckrcu/litmus
archive that are C-language and that have "Result:" comment lines
documenting expected results, comparing the actual results to
those expected. Clones the repository if it has not already
been cloned into the "tools/memory-model/litmus" directory.
initlitmushist.sh
Run all litmus tests having no more than the specified number
of processes given a specified timeout, recording the results in
.litmus.out files. Clones the repository if it has not already
been cloned into the "tools/memory-model/litmus" directory.
newlitmushist.sh
For all new or updated litmus tests having no more than the
specified number of processes given a specified timeout, run
and record the results in .litmus.out files.
checklitmushist.sh
Run all litmus tests having .litmus.out files from previous
initlitmushist.sh or newlitmushist.sh runs, comparing the
herd output to that of the original runs.
The above scripts will run litmus tests concurrently, by default with
one job per available CPU. Giving any of these scripts the --help
argument will cause them to print usage information.
This commit also adds a number of helper scripts that are not intended
to be invoked from the command line:
cmplitmushist.sh: Compare the output of two different runs of the same
litmus test.
judgelitmus.sh: Compare the output of a litmus test to its "Result:"
comment line.
parseargs.sh: Parse command-line arguments.
runlitmushist.sh: Run the litmus tests whose pathnames are provided one
per line on standard input.
While in the area, this commit also makes the existing checklitmus.sh
and checkalllitmus.sh scripts use parseargs.sh in order to provide a
bit of uniformity. In addition, per-litmus-test status output is directed
to stdout, while end-of-test summary information is directed to stderr.
Finally, the error flag standardizes on "!!!" to assist those familiar
with rcutorture output.
The defaults for the parseargs.sh arguments may be overridden by using
environment variables: LKMM_DESTDIR for --destdir, LKMM_HERD_OPTIONS
for --herdoptions, LKMM_JOBS for --jobs, LKMM_PROCS for --procs, and
LKMM_TIMEOUT for --timeout.
[ paulmck: History-check summary-line changes per Alan Stern feedback. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akiyks@gmail.com
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: parri.andrea@gmail.com
Cc: stern@rowland.harvard.edu
Cc: will.deacon@arm.com
Link: http://lkml.kernel.org/r/20181203230451.28921-2-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The kernel documents smp_mb__after_unlock_lock() the following way:
"Place this after a lock-acquisition primitive to guarantee that
an UNLOCK+LOCK pair acts as a full barrier. This guarantee applies
if the UNLOCK and LOCK are executed by the same CPU or if the
UNLOCK and LOCK operate on the same lock variable."
Formalize in LKMM the above guarantee by defining (new) mb-links according
to the law:
([M] ; po ; [UL] ; (co | po) ; [LKW] ;
fencerel(After-unlock-lock) ; [M])
where the component ([UL] ; co ; [LKW]) identifies "UNLOCK+LOCK pairs on
the same lock variable" and the component ([UL] ; po ; [LKW]) identifies
"UNLOCK+LOCK pairs executed by the same CPU".
In particular, the LKMM forbids the following two behaviors (the second
litmus test below is based on:
Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.html
c.f., Section "Tree RCU Grace Period Memory Ordering Building Blocks"):
C after-unlock-lock-same-cpu
(*
* Result: Never
*)
{}
P0(spinlock_t *s, spinlock_t *t, int *x, int *y)
{
int r0;
spin_lock(s);
WRITE_ONCE(*x, 1);
spin_unlock(s);
spin_lock(t);
smp_mb__after_unlock_lock();
r0 = READ_ONCE(*y);
spin_unlock(t);
}
P1(int *x, int *y)
{
int r0;
WRITE_ONCE(*y, 1);
smp_mb();
r0 = READ_ONCE(*x);
}
exists (0:r0=0 /\ 1:r0=0)
C after-unlock-lock-same-lock-variable
(*
* Result: Never
*)
{}
P0(spinlock_t *s, int *x, int *y)
{
int r0;
spin_lock(s);
WRITE_ONCE(*x, 1);
r0 = READ_ONCE(*y);
spin_unlock(s);
}
P1(spinlock_t *s, int *y, int *z)
{
int r0;
spin_lock(s);
smp_mb__after_unlock_lock();
WRITE_ONCE(*y, 1);
r0 = READ_ONCE(*z);
spin_unlock(s);
}
P2(int *z, int *x)
{
int r0;
WRITE_ONCE(*z, 1);
smp_mb();
r0 = READ_ONCE(*x);
}
exists (0:r0=0 /\ 1:r0=0 /\ 2:r0=0)
Signed-off-by: Andrea Parri <andrea.parri@amarulasolutions.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Daniel Lustig <dlustig@nvidia.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/20181203230451.28921-1-paulmck@linux.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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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>
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Correct a typo in OF device ID table
The last one should be 'ti,tmp442'
Signed-off-by: Cheng-Min Ao <tony_ao@wiwynn.com>
Signed-off-by: Yu-Hsiang Chen <matt_chen@wiwynn.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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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: 341f741f04be ("afs: Refcount the afs_call struct")
Signed-off-by: David Howells <dhowells@redhat.com>
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Provide a function to get a reference on an afs_call struct.
Signed-off-by: David Howells <dhowells@redhat.com>
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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: 0fafdc9f888b ("afs: Fix file locking")
Signed-off-by: David Howells <dhowells@redhat.com>
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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: ae3b7361dc0e ("afs: Fix validation/callback interaction")
Signed-off-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
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Commit c3ff2a5193fa ("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 e07db28eea38 ("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 e07db28eea38 ("kbuild: fix single target
build for external module"), and then this commit.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=201891
Fixes: e07db28eea38 ("kbuild: fix single target build for external module")
Fixes: c3ff2a5193fa ("powerpc/32: add stack protector support")
Fixes: 189af4657186 ("ARM: smp: add support for per-task stack canaries")
Fixes: 0a1213fa7432 ("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>
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- 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>
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- 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>
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From: Casey Schaufler <casey@schaufler-ca.com>
Check that the cred security blob has been set before trying
to clean it up. There is a case during credential initialization
that could result in this.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.morris@microsoft.com>
Reported-by: syzbot+69ca07954461f189e808@syzkaller.appspotmail.com
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[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 923fe4951282cbdfce05186c10380bbc45b5e03b)
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It's possible that a pid has died before we take the rcu lock, in which
case we can't walk the ancestry list as it may be detached. Instead, check
for death first before doing the walk.
Reported-by: syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com
Fixes: 2d514487faf1 ("security: Yama LSM")
Cc: stable@vger.kernel.org
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <james.morris@microsoft.com>
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As reported, the SPDX license id is not placed correctly and the variant
of the BSD License used should be specified.
Fixes: c16292578ffa ("dt-bindings: reset: Add bindings for the Meson-AXG SoC Reset Controller")
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rob Herring <robh@kernel.org>
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Fix few trivial language typos in bindings.
Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
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The cp110-system-controller0.txt file was renamed to
cp110-system-controller.txt.
Fixes: 4aa5496980e4 ("dt-bindings: cp110: rename cp110 syscon file")
Signed-off-by: Otto Sabart <ottosabart@seberm.com>
Signed-off-by: Rob Herring <robh@kernel.org>
|
Willy Tarreau
Paul E. McKenney
Zhang, Jun
Paul E. McKenney
Andrea Parri
Kangjie Lu
Cheng-Min Ao
David Howells
Marc Dionne
Masahiro Yamada
James Morris
David Francis
Kees Cook
Jerome Brunet
Krzysztof Kozlowski
Otto Sabart