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Daniel Wagner reported a crash on the BeagleBone Black SoC.
This is a single CPU architecture, and does not have a functional
arch_send_call_function_single_ipi() implementation which can crash
the kernel if that is called.
As it only has one CPU, it shouldn't be called, but if the kernel is
compiled for SMP, the push/pull RT scheduling logic now calls it for
irq_work if the one CPU is overloaded, it can use that function to call
itself and crash the kernel.
Ideally, we should disable the SCHED_FEAT(RT_PUSH_IPI) if the system
only has a single CPU. But SCHED_FEAT is a constant if sched debugging
is turned off. Another fix can also be used, and this should also help
with normal SMP machines. That is, do not initiate the pull code if
there's only one RT overloaded CPU, and that CPU happens to be the
current CPU that is scheduling in a lower priority task.
Even on a system with many CPUs, if there's many RT tasks waiting to
run on a single CPU, and that CPU schedules in another RT task of lower
priority, it will initiate the PULL logic in case there's a higher
priority RT task on another CPU that is waiting to run. But if there is
no other CPU with waiting RT tasks, it will initiate the RT pull logic
on itself (as it still has RT tasks waiting to run). This is a wasted
effort.
Not only does this help with SMP code where the current CPU is the only
one with RT overloaded tasks, it should also solve the issue that
Daniel encountered, because it will prevent the PULL logic from
executing, as there's only one CPU on the system, and the check added
here will cause it to exit the RT pull code.
Reported-by: Daniel Wagner <wagi@monom.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: stable@vger.kernel.org
Fixes: 4bdced5c9 ("sched/rt: Simplify the IPI based RT balancing logic")
Link: http://lkml.kernel.org/r/20171202130454.4cbbfe8d@vmware.local.home
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Two kernel headers got modified recently, which are used by tooling as well:
tools/include/uapi/linux/kvm.h
arch/x86/include/asm/cpufeatures.h
None of those changes have an effect on tooling, so do a plain copy.
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This fixes the following warning:
warning: objtool: x86 instruction decoder differs from kernel
Note that there are cleanups queued up for v4.16 that will make this
warning more informative and will make the syncing easier as well.
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
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Update x86-opcode-map.txt based on the October 2017 Intel SDM publication.
Fix INVPID to INVVPID.
Add UD0 and UD1 instruction opcodes.
Also sync the objtool and perf tooling copies of this file.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <masami.hiramatsu@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/aac062d7-c0f6-96e3-5c92-ed299e2bd3da@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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My previous attempt to fix a couple of bugs in __restore_processor_context():
5b06bbcfc2c6 ("x86/power: Fix some ordering bugs in __restore_processor_context()")
... introduced yet another bug, breaking suspend-resume.
Rather than trying to come up with a minimal fix, let's try to clean it up
for real. This patch fixes quite a few things:
- The old code saved a nonsensical subset of segment registers.
The only registers that need to be saved are those that contain
userspace state or those that can't be trivially restored without
percpu access working. (On x86_32, we can restore percpu access
by writing __KERNEL_PERCPU to %fs. On x86_64, it's easier to
save and restore the kernel's GSBASE.) With this patch, we
restore hardcoded values to the kernel state where applicable and
explicitly restore the user state after fixing all the descriptor
tables.
- We used to use an unholy mix of inline asm and C helpers for
segment register access. Let's get rid of the inline asm.
This fixes the reported s2ram hangs and make the code all around
more logical.
Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Reported-by: Pavel Machek <pavel@ucw.cz>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Fixes: 5b06bbcfc2c6 ("x86/power: Fix some ordering bugs in __restore_processor_context()")
Link: http://lkml.kernel.org/r/398ee68e5c0f766425a7b746becfc810840770ff.1513286253.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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x86_64 restores system call MSRs in fix_processor_context(), and
x86_32 restored them along with segment registers. The 64-bit
variant makes more sense, so move the 32-bit code to match the
64-bit code.
No side effects are expected to runtime behavior.
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/65158f8d7ee64dd6bbc6c1c83b3b34aaa854e3ae.1513286253.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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x86_64's saved_context nonsensically used separate idt_limit and
idt_base fields and then cast &idt_limit to struct desc_ptr *.
This was correct (with -fno-strict-aliasing), but it's confusing,
served no purpose, and required #ifdeffery. Simplify this by
using struct desc_ptr directly.
No change in functionality.
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Link: http://lkml.kernel.org/r/967909ce38d341b01d45eff53e278e2728a3a93a.1513286253.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The stack tracer records a stack dump whenever it sees a stack usage that is
more than what it ever saw before. This can happen at any function that is
being traced. If it happens when the CPU is going idle (or other strange
locations), RCU may not be watching, and in this case, the recording of the
stack trace will trigger a warning. There's been lots of efforts to make
hacks to allow stack tracing to proceed even if RCU is not watching, but
this only causes more issues to appear. Simply do not trace a stack if RCU
is not watching. It probably isn't a bad stack anyway.
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
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gcc toggle -fisolate-erroneous-paths-dereference (default at -O2
onwards) isolates faulty code paths such as null pointer access, divide
by zero etc. If gcc port doesnt implement __builtin_trap, an abort() is
generated which causes kernel link error.
In this case, gcc is generating abort due to 'divide by zero' in
lib/mpi/mpih-div.c.
Currently 'frv' and 'arc' are failing. Previously other arch was also
broken like m32r was fixed by commit d22e3d69ee1a ("m32r: fix build
failure").
Let's define this weak function which is common for all arch and fix the
problem permanently. We can even remove the arch specific 'abort' after
this is done.
Link: http://lkml.kernel.org/r/1513118956-8718-1-git-send-email-sudipm.mukherjee@gmail.com
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Alexey Brodkin <Alexey.Brodkin@synopsys.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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David Rientjes has reported the following memory corruption while the
oom reaper tries to unmap the victims address space
BUG: Bad page map in process oom_reaper pte:6353826300000000 pmd:00000000
addr:00007f50cab1d000 vm_flags:08100073 anon_vma:ffff9eea335603f0 mapping: (null) index:7f50cab1d
file: (null) fault: (null) mmap: (null) readpage: (null)
CPU: 2 PID: 1001 Comm: oom_reaper
Call Trace:
unmap_page_range+0x1068/0x1130
__oom_reap_task_mm+0xd5/0x16b
oom_reaper+0xff/0x14c
kthread+0xc1/0xe0
Tetsuo Handa has noticed that the synchronization inside exit_mmap is
insufficient. We only synchronize with the oom reaper if
tsk_is_oom_victim which is not true if the final __mmput is called from
a different context than the oom victim exit path. This can trivially
happen from context of any task which has grabbed mm reference (e.g. to
read /proc/<pid>/ file which requires mm etc.).
The race would look like this
oom_reaper oom_victim task
mmget_not_zero
do_exit
mmput
__oom_reap_task_mm mmput
__mmput
exit_mmap
remove_vma
unmap_page_range
Fix this issue by providing a new mm_is_oom_victim() helper which
operates on the mm struct rather than a task. Any context which
operates on a remote mm struct should use this helper in place of
tsk_is_oom_victim. The flag is set in mark_oom_victim and never cleared
so it is stable in the exit_mmap path.
Debugged by Tetsuo Handa.
Link: http://lkml.kernel.org/r/20171210095130.17110-1-mhocko@kernel.org
Fixes: 212925802454 ("mm: oom: let oom_reap_task and exit_mmap run concurrently")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: David Rientjes <rientjes@google.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Andrea Argangeli <andrea@kernel.org>
Cc: <stable@vger.kernel.org> [4.14]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In testing, we found that nfsd threads may call set_groups in parallel
for the same entry cached in auth.unix.gid, racing in the call of
groups_sort, corrupting the groups for that entry and leading to
permission denials for the client.
This patch:
- Make groups_sort globally visible.
- Move the call to groups_sort to the modifiers of group_info
- Remove the call to groups_sort from set_groups
Link: http://lkml.kernel.org/r/20171211151420.18655-1-thiago.becker@gmail.com
Signed-off-by: Thiago Rafael Becker <thiago.becker@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A semaphore is acquired before this check, so we must release it before
leaving.
Link: http://lkml.kernel.org/r/20171211211009.4971-1-christophe.jaillet@wanadoo.fr
Fixes: b7f0554a56f2 ("mm: fail get_vaddr_frames() for filesystem-dax mappings")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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On some linux distributions, the default link of sh is dash which
deoesn't support split array like "${var//,/ }"
It's better to force to use bash shell directly.
Link: http://lkml.kernel.org/r/20171208093751.GA175471@sofia
Signed-off-by: Liu Changcheng <changcheng.liu@intel.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix a silly copy-paste bug. We truncated u32 args to u16.
Link: http://lkml.kernel.org/r/20171207101134.107168-1-dvyukov@google.com
Fixes: ded97d2c2b2c ("kcov: support comparison operands collection")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Cc: syzkaller@googlegroups.com
Cc: Alexander Potapenko <glider@google.com>
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If CONFIG_DEBUG_SLAB/CONFIG_DEBUG_SLAB_LEAK are enabled, the slab code
prints extra debug information when e.g. corruption is detected. This
includes pointers, which are not very useful when hashed.
Fix this by using %px to print unhashed pointers instead where it makes
sense, and by removing the printing of a last user pointer referring to
code.
[geert+renesas@glider.be: v2]
Link: http://lkml.kernel.org/r/1513179267-2509-1-git-send-email-geert+renesas@glider.be
Link: http://lkml.kernel.org/r/1512641861-5113-1-git-send-email-geert+renesas@glider.be
Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Tobin C . Harding" <me@tobin.cc>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since commit 9cca35d42eb6 ("mm, page_alloc: enable/disable IRQs once
when freeing a list of pages") we see excessive IRQ disabled times of up
to 25ms on an embedded ARM system (tracing overhead included).
This is due to graphics buffers being freed back to the system via
release_pages(). Graphics buffers can be huge, so it's not hard to hit
cases where the list of pages to free has 2048 entries. Disabling IRQs
while freeing all those pages is clearly not a good idea.
Introduce a batch limit, which allows IRQ servicing once every few
pages. The batch count is the same as used in other parts of the MM
subsystem when dealing with IRQ disabled regions.
Link: http://lkml.kernel.org/r/20171207170314.4419-1-l.stach@pengutronix.de
Fixes: 9cca35d42eb6 ("mm, page_alloc: enable/disable IRQs once when freeing a list of pages")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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With gcc 4.1.2:
mm/memory.o: In function `wp_huge_pmd':
memory.c:(.text+0x9b4): undefined reference to `do_huge_pmd_wp_page'
Interestingly, wp_huge_pmd() is emitted in the assembler output, but
never called.
Apparently replacing the call to pmd_write() in __handle_mm_fault() by a
call to the more complex pmd_access_permitted() reduced the ability of
the compiler to remove unused code.
Fix this by marking wp_huge_pmd() inline, like was done in commit
91a90140f998 ("mm/memory.c: mark create_huge_pmd() inline to prevent
build failure") for a similar problem.
[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/1512335500-10889-1-git-send-email-geert@linux-m68k.org
Fixes: c7da82b894e9eef6 ("mm: replace pmd_write with pmd_access_permitted in fault + gup paths")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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faddr2line hit var unbound error when CROSS_COMPILE isn't set since
nounset option is set in bash script.
Link: http://lkml.kernel.org/r/20171206013022.GA83929@sofia
Fixes: 95a879825419 ("scripts/faddr2line: extend usage on generic arch")
Signed-off-by: Liu Changcheng <changcheng.liu@intel.com>
Reported-by: Richard Weinberger <richard.weinberger@gmail.com>
Reviewed-by: Richard Weinberger <richard@nod.at>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: NeilBrown <neilb@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Update zswap document with details on same-value filled pages
identification feature. The usage of zswap.same_filled_pages_enabled
module parameter is explained.
Link: http://lkml.kernel.org/r/20171206114852epcms5p6973b02a9f455d5d3c765eafda0fe2631@epcms5p6
Signed-off-by: Srividya Desireddy <srividya.dr@samsung.com>
Acked-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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gcc-8 warns about using strncpy() with the source size as the limit:
fs/exec.c:1223:32: error: argument to 'sizeof' in 'strncpy' call is the same expression as the source; did you mean to use the size of the destination? [-Werror=sizeof-pointer-memaccess]
This is indeed slightly suspicious, as it protects us from source
arguments without NUL-termination, but does not guarantee that the
destination is terminated.
This keeps the strncpy() to ensure we have properly padded target
buffer, but ensures that we use the correct length, by passing the
actual length of the destination buffer as well as adding a build-time
check to ensure it is exactly TASK_COMM_LEN.
There are only 23 callsites which I all reviewed to ensure this is
currently the case. We could get away with doing only the check or
passing the right length, but it doesn't hurt to do both.
Link: http://lkml.kernel.org/r/20171205151724.1764896-1-arnd@arndb.de
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Kees Cook <keescook@chromium.org>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Aleksa Sarai <asarai@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit ecc0c469f277 ("autofs: don't fail mount for transient error") was
meant to replace an 'if' with a 'switch', but instead added the 'switch'
leaving the case in place.
Link: http://lkml.kernel.org/r/87zi6wstmw.fsf@notabene.neil.brown.name
Fixes: ecc0c469f277 ("autofs: don't fail mount for transient error")
Reported-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: NeilBrown <neilb@suse.com>
Cc: Ian Kent <raven@themaw.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The hardened strlen() function causes rather large stack usage in at
least one file in the kernel, in particular when CONFIG_KASAN is
enabled:
drivers/media/usb/em28xx/em28xx-dvb.c: In function 'em28xx_dvb_init':
drivers/media/usb/em28xx/em28xx-dvb.c:2062:1: error: the frame size of 3256 bytes is larger than 204 bytes [-Werror=frame-larger-than=]
Analyzing this problem led to the discovery that gcc fails to merge the
stack slots for the i2c_board_info[] structures after we strlcpy() into
them, due to the 'noreturn' attribute on the source string length check.
I reported this as a gcc bug, but it is unlikely to get fixed for gcc-8,
since it is relatively easy to work around, and it gets triggered
rarely. An earlier workaround I did added an empty inline assembly
statement before the call to fortify_panic(), which works surprisingly
well, but is really ugly and unintuitive.
This is a new approach to the same problem, this time addressing it by
not calling the 'extern __real_strnlen()' function for string constants
where __builtin_strlen() is a compile-time constant and therefore known
to be safe.
We do this by checking if the last character in the string is a
compile-time constant '\0'. If it is, we can assume that strlen() of
the string is also constant.
As a side-effect, this should also improve the object code output for
any other call of strlen() on a string constant.
[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/20171205215143.3085755-1-arnd@arndb.de
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365
Link: https://patchwork.kernel.org/patch/9980413/
Link: https://patchwork.kernel.org/patch/9974047/
Fixes: 6974f0c4555 ("include/linux/string.h: add the option of fortified string.h functions")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Daniel Micay <danielmicay@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Martin Wilck <mwilck@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit bde5f6bc68db ("kmemleak: add scheduling point to
kmemleak_scan()") tries to rate-limit the frequency of cond_resched()
calls, but does it in a way which might incur an expensive division
operation in the inner loop. Simplify this.
Fixes: bde5f6bc68db5 ("kmemleak: add scheduling point to kmemleak_scan()")
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Add a variant of rbtree_replace_node() that maintains the leftmost cache
of struct rbtree_root_cached when replacing nodes within the rbtree.
As drm_mm is the only rb_replace_node() being used on an interval tree,
the mistake looks fairly self-contained. Furthermore the only user of
drm_mm_replace_node() is its testsuite...
Testcase: igt/drm_mm/replace
Link: http://lkml.kernel.org/r/20171122100729.3742-1-chris@chris-wilson.co.uk
Link: https://patchwork.freedesktop.org/patch/msgid/20171109212435.9265-1-chris@chris-wilson.co.uk
Fixes: f808c13fd373 ("lib/interval_tree: fast overlap detection")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The <linux/bug.h> was removed from radix-tree.h by commit f5bba9d11a25
("include/linux/radix-tree.h: remove unneeded #include <linux/bug.h>").
Since that commit, tools/testing/radix-tree/ couldn't pass compilation
due to tools/testing/radix-tree/idr.c:17: undefined reference to
WARN_ON_ONCE. This patch adds the bug.h header to idr.h to solve the
issue.
Link: http://lkml.kernel.org/r/1511963726-34070-2-git-send-email-wei.w.wang@intel.com
Fixes: f5bba9d11a2 ("include/linux/radix-tree.h: remove unneeded #include <linux/bug.h>")
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Recent rework of the virtio_mmio probe/remove paths balanced a
devm_ioremap() with an iounmap() rather than its devm variant. This ends
up corrupting the devm datastructures, and results in the following
boot-time splat on arm64 under QEMU 2.9.0:
[ 3.450397] ------------[ cut here ]------------
[ 3.453822] Trying to vfree() nonexistent vm area (00000000c05b4844)
[ 3.460534] WARNING: CPU: 1 PID: 1 at mm/vmalloc.c:1525 __vunmap+0x1b8/0x220
[ 3.475898] Kernel panic - not syncing: panic_on_warn set ...
[ 3.475898]
[ 3.493933] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.15.0-rc3 #1
[ 3.513109] Hardware name: linux,dummy-virt (DT)
[ 3.525382] Call trace:
[ 3.531683] dump_backtrace+0x0/0x368
[ 3.543921] show_stack+0x20/0x30
[ 3.547767] dump_stack+0x108/0x164
[ 3.559584] panic+0x25c/0x51c
[ 3.569184] __warn+0x29c/0x31c
[ 3.576023] report_bug+0x1d4/0x290
[ 3.586069] bug_handler.part.2+0x40/0x100
[ 3.597820] bug_handler+0x4c/0x88
[ 3.608400] brk_handler+0x11c/0x218
[ 3.613430] do_debug_exception+0xe8/0x318
[ 3.627370] el1_dbg+0x18/0x78
[ 3.634037] __vunmap+0x1b8/0x220
[ 3.648747] vunmap+0x6c/0xc0
[ 3.653864] __iounmap+0x44/0x58
[ 3.659771] devm_ioremap_release+0x34/0x68
[ 3.672983] release_nodes+0x404/0x880
[ 3.683543] devres_release_all+0x6c/0xe8
[ 3.695692] driver_probe_device+0x250/0x828
[ 3.706187] __driver_attach+0x190/0x210
[ 3.717645] bus_for_each_dev+0x14c/0x1f0
[ 3.728633] driver_attach+0x48/0x78
[ 3.740249] bus_add_driver+0x26c/0x5b8
[ 3.752248] driver_register+0x16c/0x398
[ 3.757211] __platform_driver_register+0xd8/0x128
[ 3.770860] virtio_mmio_init+0x1c/0x24
[ 3.782671] do_one_initcall+0xe0/0x398
[ 3.791890] kernel_init_freeable+0x594/0x660
[ 3.798514] kernel_init+0x18/0x190
[ 3.810220] ret_from_fork+0x10/0x18
To fix this, we can simply rip out the explicit cleanup that the devm
infrastructure will do for us when our probe function returns an error
code, or when our remove function returns.
We only need to ensure that we call put_device() if a call to
register_virtio_device() fails in the probe path.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Fixes: 7eb781b1bbb7136f ("virtio_mmio: add cleanup for virtio_mmio_probe")
Fixes: 25f32223bce5c580 ("virtio_mmio: add cleanup for virtio_mmio_remove")
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: weiping zhang <zhangweiping@didichuxing.com>
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
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Currently, the SVE field in ID_AA64PFR0_EL1 is visible
unconditionally to userspace via the CPU ID register emulation,
irrespective of the kernel config. This means that if a kernel
configured with CONFIG_ARM64_SVE=n is run on SVE-capable hardware,
userspace will see SVE reported as present in the ID regs even
though the kernel forbids execution of SVE instructions.
This patch makes the exposure of the SVE field in ID_AA64PFR0_EL1
conditional on CONFIG_ARM64_SVE=y.
Since future architecture features are likely to encounter a
similar requirement, this patch adds a suitable helper macros for
use when declaring config-conditional ID register fields.
Fixes: 43994d824e84 ("arm64/sve: Detect SVE and activate runtime support")
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reported-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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|
In ptdump_check_wx(), we pass walk_pgd() a start address of 0 (rather
than VA_START) for the init_mm. This means that any reported W&X
addresses are offset by VA_START, which is clearly wrong and can make
them appear like userspace addresses.
Fix this by telling the ptdump code that we're walking init_mm starting
at VA_START. We don't need to update the addr_markers, since these are
still valid bounds regardless.
Cc: <stable@vger.kernel.org>
Fixes: 1404d6f13e47 ("arm64: dump: Add checking for writable and exectuable pages")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Laura Abbott <labbott@redhat.com>
Reported-by: Timur Tabi <timur@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Conform two stray warning messages to the standard overlayfs: prefix.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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|
This case can been seen when creating the lease with the same objects passed.
[ 605.515097] 2 locks held by testapp/3337:
[ 605.519027] #0: (&dev->mode_config.idr_mutex){......}, at: [<ffff0000085f1664>] drm_mode_create_lease_ioctl+0x384/0x858
[ 605.530045] #1: (&dev->mode_config.idr_mutex){......}, at: [<ffff0000085f11bc>] drm_lease_destroy+0x2c/0x110
Which was causing the process to hang:
[ 605.398827] [<ffff0000080856cc>] __switch_to+0x94/0xa8
[ 605.404030] [<ffff000008c05d00>] __schedule+0x1b0/0x698
[ 605.409322] [<ffff000008c06224>] schedule+0x3c/0xa8
[ 605.414260] [<ffff000008c06628>] schedule_preempt_disabled+0x20/0x38
[ 605.420677] [<ffff000008c07370>] mutex_lock_nested+0x158/0x340
[ 605.426572] [<ffff0000085f11bc>] drm_lease_destroy+0x2c/0x110
[ 605.432389] [<ffff0000085cecf0>] drm_master_put+0xc0/0xc8
[ 605.437845] [<ffff0000085f175c>] drm_mode_create_lease_ioctl+0x47c/0x858
[ 605.444612] [<ffff0000085d4460>] drm_ioctl+0x198/0x448
[ 605.449811] [<ffff000008201134>] do_vfs_ioctl+0xa4/0x748
[ 605.455192] [<ffff000008201864>] SyS_ioctl+0x8c/0xa0
[ 605.460216] [<ffff000008082f4c>] __sys_trace_return+0x0/0x4
drm_mode_create_lease_ioctl() calls drm_lease_create() which acquires a lock
on dev->mode_config.idr_mutex. In case of failure, drm_lease_create() calls
drm_master_put() which in turn tries to acquire the same lock when calling
drm_lease_destroy().
v2: - Reverse the order at exit in case of fail, so that unlocking takes place
before dropping the reference.
- Include detail information about deadlock (Daniel Vetter)
Signed-off-by: Marius Vlad <marius-cristian.vlad@nxp.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171213181048.32719-1-marius-cristian.vlad@nxp.com
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PROBE_DEFER also uses system_wq to reprobe drivers, which means when
that again fails, and we try to flush the overall system_wq (to get
all the delayed connectore cleanup work_struct completed), we
deadlock.
Fix this by using just a single cleanup work, so that we can only
flush that one and don't block on anything else. That means a free
list plus locking, a standard pattern.
v2:
- Correctly free connectors only on last ref. Oops (Chris).
- use llist_head/node (Chris).
v3
- Add init_llist_head (Chris).
Fixes: a703c55004e1 ("drm: safely free connectors from connector_iter")
Fixes: 613051dac40d ("drm: locking&new iterators for connector_list")
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: <stable@vger.kernel.org> # v4.11+: 613051dac40d ("drm: locking&new iterators for connector_list"
Cc: <stable@vger.kernel.org> # v4.11+
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Javier Martinez Canillas <javier@dowhile0.org>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Guillaume Tucker <guillaume.tucker@collabora.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matt Hart <matthew.hart@linaro.org>
Cc: Thierry Escande <thierry.escande@collabora.co.uk>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171213124936.17914-1-daniel.vetter@ffwll.ch
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There are a set of values in the drm_display_info structure for each
connector which hold information derived from EDID. These are computed
in drm_add_display_info. Before this patch, that was only called in
drm_add_edid_modes. This meant that they were only set when EDID was
present and never reset when EDID was not, as happened when the
display was disconnected.
One of these fields, non_desktop, is used from
drm_mode_connector_update_edid_property, the function responsible for
assigning the new edid value to the application-visible property.
Various drivers call these two functions (drm_add_edid_modes and
drm_mode_connector_update_edid_property) in different orders. This
means that even when EDID is present, the drm_display_info fields may
not have been computed at the time that
drm_mode_connector_update_edid_property used the non_desktop value to
set the non_desktop property.
I've added a public function (drm_reset_display_info) that resets the
drm_display_info field values to default values and then made the
drm_add_display_info function public. These two functions are now
called directly from drm_mode_connector_update_edid_property so that
the drm_display_info fields are always computed from the current EDID
information before being used in that function.
This means that the drm_display_info values are often computed twice,
once when the EDID property it set and a second time when EDID is used
to compute modes for the device. The alternative would be to uniformly
ensure that the values were computed once before being used, which
would require that all drivers reliably invoke the two paths in the
same order. The computation is inexpensive enough that it seems more
maintainable in the long term to simply compute them in both paths.
The API to drm_add_display_info has been changed so that it no longer
takes the set of edid-based quirks as a parameter. Rather, it now
computes those quirks itself and returns them for further use by
drm_add_edid_modes.
This patch also includes a number of 'const' additions caused by
drm_mode_connector_update_edid_property taking a 'const struct edid *'
parameter and wanting to pass that along to drm_add_display_info.
v2: after review by Daniel Vetter <daniel.vetter@ffwll.ch>
Removed EXPORT_SYMBOL_GPL for drm_reset_display_info and
drm_add_display_info.
Added FIXME in drm_mode_connector_update_edid_property about
potentially merging that with drm_add_edid_modes to avoid
the need for two driver calls.
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171213084427.31199-1-keithp@keithp.com
(danvet: cherry picked from commit 12a889bf4bca ("drm: rework delayed
connector cleanup in connector_iter") from drm-misc-next since
functional conflict with changes in -next and we need to make sure
both have the right version and nothing gets lost.)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Commit:
681fbec881de ("lockdep: Use consistent printing primitives")
has moved lockdep away from using printk() for printing.
The commit added usage of pr_cont() which wasn't wrapped in the
userspace headers, causing the following warning for the
liblockdep build:
../../../kernel/locking/lockdep.c:3544:2: warning: implicit declaration of function 'pr_cont' [-Wimplicit-function-declaration]
Adding an empty declaration of 'pr_cont' fixes the problem.
Signed-off-by: Mengting Zhang <zhangmengting@huawei.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: a.p.zijlstra@chello.nl
Link: http://lkml.kernel.org/r/20171212181644.11913-2-alexander.levin@verizon.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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do_sea() calls arm64_notify_die() which will always signal
user-space. It also returns whether APEI claimed the external
abort as a RAS notification. If it returns failure do_mem_abort()
will signal user-space too.
do_mem_abort() wants to know if we handled the error, we always
call arm64_notify_die() so can always return success.
Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
Reviewed-by: James Morse <james.morse@arm.com>
Reviewed-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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|
If CONFIG_DEBUG_SLAB=y, and no PCIe card is inserted, the kernel crashes
during probe on r8a7791/koelsch:
rcar-pcie fe000000.pcie: PCIe link down
Unable to handle kernel paging request at virtual address 6b6b6b6b
(seeing this message requires earlycon and keep_bootcon).
Indeed, pci_free_host_bridge() frees the PCI host bridge, including the
embedded rcar_pcie object, so pci_free_resource_list() must not be called
afterwards.
To fix this, move the call to pci_free_resource_list() up, and update the
label name accordingly.
Fixes: ddd535f1ea3eb27e ("PCI: rcar: Fix memory leak when no PCIe card is inserted")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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|
Add a respective dependency.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
|
|
Unconditionally reporting a value seen on the P4 or older invokes
functionality like io_apic_get_unique_id() on 32-bit builds, resulting
in a panic() with sufficiently many CPUs and/or IO-APICs. Doing what
that function does would be the hypervisor's responsibility anyway, so
makes no sense to be used when running on Xen. Uniformly report a more
modern version; this shouldn't matter much as both LAPIC and IO-APIC are
being managed entirely / mostly by the hypervisor.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Now that ACCESS_ONCE() has been excised from the kernel, any uses will
result in a build error, and we no longer need to whine about it in
checkpatch.
This patch removes the newly redundant warning.
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Joe Perches <joe@perches.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@redhat.com
Link: http://lkml.kernel.org/r/20171127103824.36526-5-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
There are no longer any kernelspace uses of ACCESS_ONCE(), so we can
remove the definition from <linux/compiler.h>.
This patch removes the ACCESS_ONCE() definition, and updates comments
which referred to it. At the same time, some inconsistent and redundant
whitespace is removed from comments.
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: apw@canonical.com
Link: http://lkml.kernel.org/r/20171127103824.36526-4-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
There are no longer any usersapce uses of ACCESS_ONCE(), so we can
remove the definition from our userspace <linux/compiler.h>, which is
only used by tools in the kernel directory (i.e. it isn't a uapi
header).
This patch removes the ACCESS_ONCE() definition, and updates comments
which referred to it. At the same time, some inconsistent and redundant
whitespace is removed from comments.
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: apw@canonical.com
Link: http://lkml.kernel.org/r/20171127103824.36526-3-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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|
Recently there was a treewide conversion of ACCESS_ONCE() to
{READ,WRITE}_ONCE(), but a new use was introduced concurrently by
commit:
1695849735752d2a ("perf mmap: Move perf_mmap and methods to separate mmap.[ch] files")
Let's convert this over to READ_ONCE() so that we can remove the
ACCESS_ONCE() definitions in subsequent patches.
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: apw@canonical.com
Link: http://lkml.kernel.org/r/20171127103824.36526-2-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The only inclusion of asm/uaccess.h should be by linux/uaccess.h. All
other headers should use the latter.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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The ARM architecture defines the memory locations that are permitted
to be accessed as the result of a speculative instruction fetch from
an exception level for which all stages of translation are disabled.
Specifically, the core is permitted to speculatively fetch from the
4KB region containing the current program counter 4K and next 4K.
When translation is changed from enabled to disabled for the running
exception level (SCTLR_ELn[M] changed from a value of 1 to 0), the
Falkor core may errantly speculatively access memory locations outside
of the 4KB region permitted by the architecture. The errant memory
access may lead to one of the following unexpected behaviors.
1) A System Error Interrupt (SEI) being raised by the Falkor core due
to the errant memory access attempting to access a region of memory
that is protected by a slave-side memory protection unit.
2) Unpredictable device behavior due to a speculative read from device
memory. This behavior may only occur if the instruction cache is
disabled prior to or coincident with translation being changed from
enabled to disabled.
The conditions leading to this erratum will not occur when either of the
following occur:
1) A higher exception level disables translation of a lower exception level
(e.g. EL2 changing SCTLR_EL1[M] from a value of 1 to 0).
2) An exception level disabling its stage-1 translation if its stage-2
translation is enabled (e.g. EL1 changing SCTLR_EL1[M] from a value of 1
to 0 when HCR_EL2[VM] has a value of 1).
To avoid the errant behavior, software must execute an ISB immediately
prior to executing the MSR that will change SCTLR_ELn[M] from 1 to 0.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Add cputype definition macros for Qualcomm Datacenter Technologies
Falkor CPU in cputype.h. It's unfortunate that the first revision
of the Falkor CPU used the wrong part number 0x800, got fixed in v2
chip with part number 0xC00, and would be used the same value for
future revisions.
Signed-off-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Jiankang reports that our race detection in set_pte_at is firing when
copying the page tables in dup_mmap as a result of a fork(). In this
situation, the page table isn't actually live and so there is no way
that we can race with a concurrent update from the hardware page table
walker.
This patch reworks the race detection so that we require either the
mm to match the current active_mm (i.e. currently installed in our TTBR0)
or the mm_users count to be greater than 1, implying that the page table
could be live in another CPU. The mm_users check might still be racy,
but we'll avoid false positives and it's not realistic to validate that
all the necessary locks are held as part of this assertion.
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Reported-by: Jiankang Chen <chenjiankang1@huawei.com>
Tested-by: Jiankang Chen <chenjiankang1@huawei.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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This code (CONFIG_LOCKDEP_CROSSRELEASE=y and CONFIG_LOCKDEP_COMPLETIONS=y),
while it found a number of old bugs initially, was also causing too many
false positives that caused people to disable lockdep - which is arguably
a worse overall outcome.
If we disable cross-release by default but keep the code upstream then
in practice the most likely outcome is that we'll allow the situation
to degrade gradually, by allowing entropy to introduce more and more
false positives, until it overwhelms maintenance capacity.
Another bad side effect was that people were trying to work around
the false positives by uglifying/complicating unrelated code. There's
a marked difference between annotating locking operations and
uglifying good code just due to bad lock debugging code ...
This gradual decrease in quality happened to a number of debugging
facilities in the kernel, and lockdep is pretty complex already,
so we cannot risk this outcome.
Either cross-release checking can be done right with no false positives,
or it should not be included in the upstream kernel.
( Note that it might make sense to maintain it out of tree and go through
the false positives every now and then and see whether new bugs were
introduced. )
Cc: Byungchul Park <byungchul.park@lge.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
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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When CONFIG_GENERIC_LOCKBEAK=y, locking structures grow an extra int ->break_lock
field which is used to implement raw_spin_is_contended() by setting the field
to 1 when waiting on a lock and clearing it to zero when holding a lock.
However, there are a few problems with this approach:
- There is a write-write race between a CPU successfully taking the lock
(and subsequently writing break_lock = 0) and a waiter waiting on
the lock (and subsequently writing break_lock = 1). This could result
in a contended lock being reported as uncontended and vice-versa.
- On machines with store buffers, nothing guarantees that the writes
to break_lock are visible to other CPUs at any particular time.
- READ_ONCE/WRITE_ONCE are not used, so the field is potentially
susceptible to harmful compiler optimisations,
Consequently, the usefulness of this field is unclear and we'd be better off
removing it and allowing architectures to implement raw_spin_is_contended() by
providing a definition of arch_spin_is_contended(), as they can when
CONFIG_GENERIC_LOCKBREAK=n.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Sebastian Ott <sebott@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1511894539-7988-3-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Commit:
a8a217c22116 ("locking/core: Remove {read,spin,write}_can_lock()")
removed the definition of raw_spin_can_lock(), causing the GENERIC_LOCKBREAK
spin_lock() routines to poll the ->break_lock field when waiting on a lock.
This has been reported to cause a deadlock during boot on s390, because
the ->break_lock field is also set by the waiters, and can potentially
remain set indefinitely if no other CPUs come in to take the lock after
it has been released.
This patch removes the explicit spinning on ->break_lock from the waiters,
instead relying on the outer trylock() operation to determine when the
lock is available.
Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Tested-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: a8a217c22116 ("locking/core: Remove {read,spin,write}_can_lock()")
Link: http://lkml.kernel.org/r/1511894539-7988-2-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Avoid that scsi_show_rq() triggers a NULL pointer dereference if called
after sd_uninit_command(). Swap the NULL pointer assignment and the
mempool_free() call in sd_uninit_command() to make it less likely that
scsi_show_rq() triggers a use-after-free. Note: even with these changes
scsi_show_rq() can trigger a use-after-free but that's a lesser evil
than e.g. suppressing debug information for T10 PI Type 2 commands
completely. This patch fixes the following oops:
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: scsi_format_opcode_name+0x1a/0x1c0
CPU: 1 PID: 1881 Comm: cat Not tainted 4.14.0-rc2.blk_mq_io_hang+ #516
Call Trace:
__scsi_format_command+0x27/0xc0
scsi_show_rq+0x5c/0xc0
__blk_mq_debugfs_rq_show+0x116/0x130
blk_mq_debugfs_rq_show+0xe/0x10
seq_read+0xfe/0x3b0
full_proxy_read+0x54/0x90
__vfs_read+0x37/0x160
vfs_read+0x96/0x130
SyS_read+0x55/0xc0
entry_SYSCALL_64_fastpath+0x1a/0xa5
[mkp: added Type 2]
Fixes: 0eebd005dd07 ("scsi: Implement blk_mq_ops.show_rq()")
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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fcoe-devel@open-fcoe.org is defunct and all patches are routed via the
SCSI tree anyways.
So update MAINTAINERS accordingly.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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Steven Rostedt
Ingo Molnar
Randy Dunlap
Andy Lutomirski
Sudip Mukherjee
Michal Hocko
Thiago Rafael Becker
Christophe JAILLET
Liu, Changcheng
Dmitry Vyukov
Geert Uytterhoeven
Lucas Stach
Geert Uytterhoeven
Srividya Desireddy
Arnd Bergmann
NeilBrown
Andrew Morton
Chris Wilson
Wei Wang
Mark Rutland
Dave Martin
Amir Goldstein
Marius Vlad
Daniel Vetter
Keith Packard
Mengting Zhang
Dongjiu Geng
Jan Beulich
Will Deacon
Shanker Donthineni
Bart Van Assche
Johannes Thumshirn