No architecture terminates the stack trace with ULONG_MAX anymore. As the
code checks the number of entries stored anyway there is no point in
keeping all that ULONG_MAX magic around.
The histogram code zeroes the storage before saving the stack, so if the
trace is shorter than the maximum number of entries it can terminate the
print loop if a zero entry is detected.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Potapenko <glider@google.com>
Link: https://lkml.kernel.org/r/20190410103645.048761764@linutronix.de
Pull timer fix from Ingo Molnar:
"Fix the alarm_timer_remaining() return value"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
alarmtimer: Return correct remaining time
Pull scheduler fix from Ingo Molnar:
"Fix a NULL pointer dereference crash in certain environments"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Do not re-read ->h_load_next during hierarchical load calculation
Pull perf fixes from Ingo Molnar:
"Six kernel side fixes: three related to NMI handling on AMD systems, a
race fix, a kexec initialization fix and a PEBS sampling fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix perf_event_disable_inatomic() race
x86/perf/amd: Remove need to check "running" bit in NMI handler
x86/perf/amd: Resolve NMI latency issues for active PMCs
x86/perf/amd: Resolve race condition when disabling PMC
perf/x86/intel: Initialize TFA MSR
perf/x86/intel: Fix handling of wakeup_events for multi-entry PEBS
Pull locking fix from Ingo Molnar:
"Fixes a crash when accessing /proc/lockdep"
* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Zap lock classes even with lock debugging disabled
Thomas-Mich Richter reported he triggered a WARN()ing from event_function_local()
on his s390. The problem boils down to:
CPU-A CPU-B
perf_event_overflow()
perf_event_disable_inatomic()
@pending_disable = 1
irq_work_queue();
sched-out
event_sched_out()
@pending_disable = 0
sched-in
perf_event_overflow()
perf_event_disable_inatomic()
@pending_disable = 1;
irq_work_queue(); // FAILS
irq_work_run()
perf_pending_event()
if (@pending_disable)
perf_event_disable_local(); // WHOOPS
The problem exists in generic, but s390 is particularly sensitive
because it doesn't implement arch_irq_work_raise(), nor does it call
irq_work_run() from it's PMU interrupt handler (nor would that be
sufficient in this case, because s390 also generates
perf_event_overflow() from pmu::stop). Add to that the fact that s390
is a virtual architecture and (virtual) CPU-A can stall long enough
for the above race to happen, even if it would self-IPI.
Adding a irq_work_sync() to event_sched_in() would work for all hardare
PMUs that properly use irq_work_run() but fails for software PMUs.
Instead encode the CPU number in @pending_disable, such that we can
tell which CPU requested the disable. This then allows us to detect
the above scenario and even redirect the IPI to make up for the failed
queue.
Reported-by: Thomas-Mich Richter <tmricht@linux.ibm.com>
Tested-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With skip set to 1, I get a traceback like this:
[ 106.867637] DMA-API: Mapped at:
[ 106.870784] afu_dma_map_region+0x2cd/0x4f0 [dfl_afu]
[ 106.875839] afu_ioctl+0x258/0x380 [dfl_afu]
[ 106.880108] do_vfs_ioctl+0xa9/0x720
[ 106.883688] ksys_ioctl+0x60/0x90
[ 106.887007] __x64_sys_ioctl+0x16/0x20
With the previous value of 2, afu_dma_map_region was being omitted. I
suspect that the code paths have simply changed since the value of 2 was
chosen a decade ago, but it's also possible that it varies based on which
mapping function was used, compiler inlining choices, etc. In any case,
it's best to err on the side of skipping less.
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
The following commit:
a0b0fd53e1 ("locking/lockdep: Free lock classes that are no longer in use")
changed the behavior of lockdep_free_key_range() from
unconditionally zapping lock classes into only zapping lock classes if
debug_lock == true. Not zapping lock classes if debug_lock == false leaves
dangling pointers in several lockdep datastructures, e.g. lock_class::name
in the all_lock_classes list.
The shell command "cat /proc/lockdep" causes the kernel to iterate the
all_lock_classes list. Hence the "unable to handle kernel paging request" cash
that Shenghui encountered by running cat /proc/lockdep.
Since the new behavior can cause cat /proc/lockdep to crash, restore the
pre-v5.1 behavior.
This patch avoids that cat /proc/lockdep triggers the following crash
with debug_lock == false:
BUG: unable to handle kernel paging request at fffffbfff40ca448
RIP: 0010:__asan_load1+0x28/0x50
Call Trace:
string+0xac/0x180
vsnprintf+0x23e/0x820
seq_vprintf+0x82/0xc0
seq_printf+0x92/0xb0
print_name+0x34/0xb0
l_show+0x184/0x200
seq_read+0x59e/0x6c0
proc_reg_read+0x11f/0x170
__vfs_read+0x4d/0x90
vfs_read+0xc5/0x1f0
ksys_read+0xab/0x130
__x64_sys_read+0x43/0x50
do_syscall_64+0x71/0x210
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Reported-by: shenghui <shhuiw@foxmail.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: a0b0fd53e1 ("locking/lockdep: Free lock classes that are no longer in use") # v5.1-rc1.
Link: https://lkml.kernel.org/r/20190403233552.124673-1-bvanassche@acm.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Merge misc fixes from Andrew Morton:
"14 fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kernel/sysctl.c: fix out-of-bounds access when setting file-max
mm/util.c: fix strndup_user() comment
sh: fix multiple function definition build errors
MAINTAINERS: add maintainer and replacing reviewer ARM/NUVOTON NPCM
MAINTAINERS: fix bad pattern in ARM/NUVOTON NPCM
mm: writeback: use exact memcg dirty counts
psi: clarify the units used in pressure files
mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()
hugetlbfs: fix memory leak for resv_map
mm: fix vm_fault_t cast in VM_FAULT_GET_HINDEX()
lib/lzo: fix bugs for very short or empty input
include/linux/bitrev.h: fix constant bitrev
kmemleak: powerpc: skip scanning holes in the .bss section
lib/string.c: implement a basic bcmp
Commit 32a5ad9c22 ("sysctl: handle overflow for file-max") hooked up
min/max values for the file-max sysctl parameter via the .extra1 and
.extra2 fields in the corresponding struct ctl_table entry.
Unfortunately, the minimum value points at the global 'zero' variable,
which is an int. This results in a KASAN splat when accessed as a long
by proc_doulongvec_minmax on 64-bit architectures:
| BUG: KASAN: global-out-of-bounds in __do_proc_doulongvec_minmax+0x5d8/0x6a0
| Read of size 8 at addr ffff2000133d1c20 by task systemd/1
|
| CPU: 0 PID: 1 Comm: systemd Not tainted 5.1.0-rc3-00012-g40b114779944 #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0x0/0x228
| show_stack+0x14/0x20
| dump_stack+0xe8/0x124
| print_address_description+0x60/0x258
| kasan_report+0x140/0x1a0
| __asan_report_load8_noabort+0x18/0x20
| __do_proc_doulongvec_minmax+0x5d8/0x6a0
| proc_doulongvec_minmax+0x4c/0x78
| proc_sys_call_handler.isra.19+0x144/0x1d8
| proc_sys_write+0x34/0x58
| __vfs_write+0x54/0xe8
| vfs_write+0x124/0x3c0
| ksys_write+0xbc/0x168
| __arm64_sys_write+0x68/0x98
| el0_svc_common+0x100/0x258
| el0_svc_handler+0x48/0xc0
| el0_svc+0x8/0xc
|
| The buggy address belongs to the variable:
| zero+0x0/0x40
|
| Memory state around the buggy address:
| ffff2000133d1b00: 00 00 00 00 00 00 00 00 fa fa fa fa 04 fa fa fa
| ffff2000133d1b80: fa fa fa fa 04 fa fa fa fa fa fa fa 04 fa fa fa
| >ffff2000133d1c00: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00
| ^
| ffff2000133d1c80: fa fa fa fa 00 fa fa fa fa fa fa fa 00 00 00 00
| ffff2000133d1d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Fix the splat by introducing a unsigned long 'zero_ul' and using that
instead.
Link: http://lkml.kernel.org/r/20190403153409.17307-1-will.deacon@arm.com
Fixes: 32a5ad9c22 ("sysctl: handle overflow for file-max")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Christian Brauner <christian@brauner.io>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull syscall-get-arguments cleanup and fixes from Steven Rostedt:
"Andy Lutomirski approached me to tell me that the
syscall_get_arguments() implementation in x86 was horrible and gcc
certainly gets it wrong.
He said that since the tracepoints only pass in 0 and 6 for i and n
repectively, it should be optimized for that case. Inspecting the
kernel, I discovered that all users pass in 0 for i and only one file
passing in something other than 6 for the number of arguments. That
code happens to be my own code used for the special syscall tracing.
That can easily be converted to just using 0 and 6 as well, and only
copying what is needed. Which is probably the faster path anyway for
that case.
Along the way, a couple of real fixes came from this as the
syscall_get_arguments() function was incorrect for csky and riscv.
x86 has been optimized to for the new interface that removes the
variable number of arguments, but the other architectures could still
use some loving and take more advantage of the simpler interface"
* tag 'trace-5.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
syscalls: Remove start and number from syscall_set_arguments() args
syscalls: Remove start and number from syscall_get_arguments() args
csky: Fix syscall_get_arguments() and syscall_set_arguments()
riscv: Fix syscall_get_arguments() and syscall_set_arguments()
tracing/syscalls: Pass in hardcoded 6 into syscall_get_arguments()
ptrace: Remove maxargs from task_current_syscall()
If a child irqchip calls irq_chip_set_wake_parent() but its parent irqchip
has the IRQCHIP_SKIP_SET_WAKE flag set an error is returned.
This is inconsistent behaviour vs. set_irq_wake_real() which returns 0 when
the irqchip has the IRQCHIP_SKIP_SET_WAKE flag set. It doesn't attempt to
walk the chain of parents and set irq wake on any chips that don't have the
flag set either. If the intent is to call the .irq_set_wake() callback of
the parent irqchip, then we expect irqchip implementations to omit the
IRQCHIP_SKIP_SET_WAKE flag and implement an .irq_set_wake() function that
calls irq_chip_set_wake_parent().
The problem has been observed on a Qualcomm sdm845 device where set wake
fails on any GPIO interrupts after applying work in progress wakeup irq
patches to the GPIO driver. The chain of chips looks like this:
QCOM GPIO -> QCOM PDC (SKIP) -> ARM GIC (SKIP)
The GPIO controllers parent is the QCOM PDC irqchip which in turn has ARM
GIC as parent. The QCOM PDC irqchip has the IRQCHIP_SKIP_SET_WAKE flag
set, and so does the grandparent ARM GIC.
The GPIO driver doesn't know if the parent needs to set wake or not, so it
unconditionally calls irq_chip_set_wake_parent() causing this function to
return a failure because the parent irqchip (PDC) doesn't have the
.irq_set_wake() callback set. Returning 0 instead makes everything work and
irqs from the GPIO controller can be configured for wakeup.
Make it consistent by returning 0 (success) from irq_chip_set_wake_parent()
when a parent chip has IRQCHIP_SKIP_SET_WAKE set.
[ tglx: Massaged changelog ]
Fixes: 08b55e2a92 ("genirq: Add irqchip_set_wake_parent")
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-gpio@vger.kernel.org
Cc: Lina Iyer <ilina@codeaurora.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190325181026.247796-1-swboyd@chromium.org
