01 Sep, 2020
1 commit
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The current notifiers have the following error handling pattern all
over the place:int err, nr;
err = __foo_notifier_call_chain(&chain, val_up, v, -1, &nr);
if (err & NOTIFIER_STOP_MASK)
__foo_notifier_call_chain(&chain, val_down, v, nr-1, NULL)And aside from the endless repetition thereof, it is broken. Consider
blocking notifiers; both calls take and drop the rwsem, this means
that the notifier list can change in between the two calls, making @nr
meaningless.Fix this by replacing all the __foo_notifier_call_chain() functions
with foo_notifier_call_chain_robust() that embeds the above pattern,
but ensures it is inside a single lock region.Note: I switched atomic_notifier_call_chain_robust() to use
the spinlock, since RCU cannot provide the guarantee
required for the recovery.Note: software_resume() error handling was broken afaict.
Signed-off-by: Peter Zijlstra (Intel)
Signed-off-by: Ingo Molnar
Acked-by: Rafael J. Wysocki
Link: https://lore.kernel.org/r/20200818135804.325626653@infradead.org
03 Jun, 2020
1 commit
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These functions are not needed anymore because the vmalloc and ioremap
mappings are now synchronized when they are created or torn down.Remove all callers and function definitions.
Signed-off-by: Joerg Roedel
Signed-off-by: Andrew Morton
Tested-by: Steven Rostedt (VMware)
Acked-by: Andy Lutomirski
Acked-by: Peter Zijlstra (Intel)
Cc: Arnd Bergmann
Cc: Christoph Hellwig
Cc: Dave Hansen
Cc: "H . Peter Anvin"
Cc: Ingo Molnar
Cc: Matthew Wilcox (Oracle)
Cc: Michal Hocko
Cc: "Rafael J. Wysocki"
Cc: Thomas Gleixner
Cc: Vlastimil Babka
Link: http://lkml.kernel.org/r/20200515140023.25469-7-joro@8bytes.org
Signed-off-by: Linus Torvalds
22 Mar, 2020
1 commit
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Commit 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in
__purge_vmap_area_lazy()") introduced a call to vmalloc_sync_all() in
the vunmap() code-path. While this change was necessary to maintain
correctness on x86-32-pae kernels, it also adds additional cycles for
architectures that don't need it.Specifically on x86-64 with CONFIG_VMAP_STACK=y some people reported
severe performance regressions in micro-benchmarks because it now also
calls the x86-64 implementation of vmalloc_sync_all() on vunmap(). But
the vmalloc_sync_all() implementation on x86-64 is only needed for newly
created mappings.To avoid the unnecessary work on x86-64 and to gain the performance
back, split up vmalloc_sync_all() into two functions:* vmalloc_sync_mappings(), and
* vmalloc_sync_unmappings()Most call-sites to vmalloc_sync_all() only care about new mappings being
synchronized. The only exception is the new call-site added in the
above mentioned commit.Shile Zhang directed us to a report of an 80% regression in reaim
throughput.Fixes: 3f8fd02b1bf1 ("mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy()")
Reported-by: kernel test robot
Reported-by: Shile Zhang
Signed-off-by: Joerg Roedel
Signed-off-by: Andrew Morton
Tested-by: Borislav Petkov
Acked-by: Rafael J. Wysocki [GHES]
Cc: Dave Hansen
Cc: Andy Lutomirski
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc:
Link: http://lkml.kernel.org/r/20191009124418.8286-1-joro@8bytes.org
Link: https://lists.01.org/hyperkitty/list/lkp@lists.01.org/thread/4D3JPPHBNOSPFK2KEPC6KGKS6J25AIDB/
Link: http://lkml.kernel.org/r/20191113095530.228959-1-shile.zhang@linux.alibaba.com
Signed-off-by: Linus Torvalds
05 Dec, 2019
3 commits
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blocking_notifier_chain_cond_register() does not consider system_booting
state, which is the only difference between this function and
blocking_notifier_cain_register(). This can be a bug and is a piece of
duplicate code.Delete blocking_notifier_chain_cond_register()
Link: http://lkml.kernel.org/r/1568861888-34045-4-git-send-email-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni
Reviewed-by: Andrew Morton
Cc: Alan Stern
Cc: Alexey Dobriyan
Cc: Andy Lutomirski
Cc: Anna Schumaker
Cc: Arjan van de Ven
Cc: Chuck Lever
Cc: David S. Miller
Cc: Ingo Molnar
Cc: J. Bruce Fields
Cc: Jeff Layton
Cc: Nadia Derbey
Cc: "Paul E. McKenney"
Cc: Sam Protsenko
Cc: Thomas Gleixner
Cc: Trond Myklebust
Cc: Vasily Averin
Cc: Viresh Kumar
Cc: YueHaibing
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The only difference between notifier_chain_cond_register() and
notifier_chain_register() is the lack of warning hints for duplicate
registrations. Use notifier_chain_register() instead of
notifier_chain_cond_register() to avoid duplicate codeLink: http://lkml.kernel.org/r/1568861888-34045-3-git-send-email-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni
Reviewed-by: Andrew Morton
Cc: Alan Stern
Cc: Alexey Dobriyan
Cc: Andy Lutomirski
Cc: Anna Schumaker
Cc: Arjan van de Ven
Cc: Chuck Lever
Cc: David S. Miller
Cc: Ingo Molnar
Cc: J. Bruce Fields
Cc: Jeff Layton
Cc: Nadia Derbey
Cc: "Paul E. McKenney"
Cc: Sam Protsenko
Cc: Thomas Gleixner
Cc: Trond Myklebust
Cc: Vasily Averin
Cc: Viresh Kumar
Cc: YueHaibing
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Registering the same notifier to a hook repeatedly can cause the hook
list to form a ring or lose other members of the list.case1: An infinite loop in notifier_chain_register() can cause soft lockup
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test2);case2: An infinite loop in notifier_chain_register() can cause soft lockup
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_call_chain(&test_notifier_list, 0, NULL);case3: lose other hook test2
atomic_notifier_chain_register(&test_notifier_list, &test1);
atomic_notifier_chain_register(&test_notifier_list, &test2);
atomic_notifier_chain_register(&test_notifier_list, &test1);case4: Unregister returns 0, but the hook is still in the linked list,
and it is not really registered. If you call
notifier_call_chain after ko is unloaded, it will trigger oops.If the system is configured with softlockup_panic and the same hook is
repeatedly registered on the panic_notifier_list, it will cause a loop
panic.Add a check in notifier_chain_register(), intercepting duplicate
registrations to avoid infinite loopsLink: http://lkml.kernel.org/r/1568861888-34045-2-git-send-email-nixiaoming@huawei.com
Signed-off-by: Xiaoming Ni
Reviewed-by: Vasily Averin
Reviewed-by: Andrew Morton
Cc: Alexey Dobriyan
Cc: Anna Schumaker
Cc: Arjan van de Ven
Cc: J. Bruce Fields
Cc: Chuck Lever
Cc: David S. Miller
Cc: Jeff Layton
Cc: Andy Lutomirski
Cc: Ingo Molnar
Cc: Nadia Derbey
Cc: "Paul E. McKenney"
Cc: Sam Protsenko
Cc: Alan Stern
Cc: Thomas Gleixner
Cc: Trond Myklebust
Cc: Viresh Kumar
Cc: Xiaoming Ni
Cc: YueHaibing
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
21 May, 2019
1 commit
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Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the fileThese files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:GPL-2.0-only
Signed-off-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
15 May, 2019
1 commit
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By design notifiers can be registerd once only, 2nd register attempt
called by mistake silently corrupts notifiers list.A few years ago I investigated described problem, the host was power
cycled because of notifier list corruption. I've prepared this patch
and applied it to the OpenVZ kernel and sent this patch but nobody
commented on it. Later it helped us to detect a similar problem in the
OpenVz kernel.Mistakes with notifier registration can happen for example during
subsystem initialization from different namespaces, or because of a lost
unregister in the roll-back path on initialization failures.The proposed check cannot prevent the described problem, however it
allows us to detect its reason quickly without coredump analysis.Link: http://lkml.kernel.org/r/04127e71-4782-9bbb-fe5a-7c01e93a99b0@virtuozzo.com
Signed-off-by: Vasily Averin
Reviewed-by: Andrew Morton
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Feb, 2017
1 commit
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NOTIFY_STOP_MASK (0x8000) has only one bit set and there is no need to
compare output of "ret & NOTIFY_STOP_MASK" to NOTIFY_STOP_MASK. We just
need to make sure the output is non-zero, that's it.Link: http://lkml.kernel.org/r/88ee58264a2bfab1c97ffc8ac753e25f55f57c10.1483593065.git.viresh.kumar@linaro.org
Signed-off-by: Viresh Kumar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Sep, 2015
1 commit
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Pull x86 asm changes from Ingo Molnar:
"The biggest changes in this cycle were:- Revamp, simplify (and in some cases fix) Time Stamp Counter (TSC)
primitives. (Andy Lutomirski)- Add new, comprehensible entry and exit handlers written in C.
(Andy Lutomirski)- vm86 mode cleanups and fixes. (Brian Gerst)
- 32-bit compat code cleanups. (Brian Gerst)
The amount of simplification in low level assembly code is already
palpable:arch/x86/entry/entry_32.S | 130 +----
arch/x86/entry/entry_64.S | 197 ++-----but more simplifications are planned.
There's also the usual laudry mix of low level changes - see the
changelog for details"* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (83 commits)
x86/asm: Drop repeated macro of X86_EFLAGS_AC definition
x86/asm/msr: Make wrmsrl() a function
x86/asm/delay: Introduce an MWAITX-based delay with a configurable timer
x86/asm: Add MONITORX/MWAITX instruction support
x86/traps: Weaken context tracking entry assertions
x86/asm/tsc: Add rdtscll() merge helper
selftests/x86: Add syscall_nt selftest
selftests/x86: Disable sigreturn_64
x86/vdso: Emit a GNU hash
x86/entry: Remove do_notify_resume(), syscall_trace_leave(), and their TIF masks
x86/entry/32: Migrate to C exit path
x86/entry/32: Remove 32-bit syscall audit optimizations
x86/vm86: Rename vm86->v86flags and v86mask
x86/vm86: Rename vm86->vm86_info to user_vm86
x86/vm86: Clean up vm86.h includes
x86/vm86: Move the vm86 IRQ definitions to vm86.h
x86/vm86: Use the normal pt_regs area for vm86
x86/vm86: Eliminate 'struct kernel_vm86_struct'
x86/vm86: Move fields from 'struct kernel_vm86_struct' to 'struct vm86'
x86/vm86: Move vm86 fields out of 'thread_struct'
...
07 Jul, 2015
1 commit
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Low-level arch entries often call notify_die(), and it's easy for
arch code to fail to exit an RCU quiescent state first. Assert
that we're not quiescent in notify_die().Signed-off-by: Andy Lutomirski
Cc: Andy Lutomirski
Cc: Borislav Petkov
Cc: Brian Gerst
Cc: Denys Vlasenko
Cc: Denys Vlasenko
Cc: Frederic Weisbecker
Cc: H. Peter Anvin
Cc: Paul E. McKenney
Cc: Kees Cook
Cc: Linus Torvalds
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Rik van Riel
Cc: Thomas Gleixner
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1f5fe6c23d5b432a23267102f2d72b787d80fdd8.1435952415.git.luto@kernel.org
Signed-off-by: Ingo Molnar
07 Jan, 2015
1 commit
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SRCU is not necessary to be compiled by default in all cases. For tinification
efforts not compiling SRCU unless necessary is desirable.The current patch tries to make compiling SRCU optional by introducing a new
Kconfig option CONFIG_SRCU which is selected when any of the components making
use of SRCU are selected.If we do not select CONFIG_SRCU, srcu.o will not be compiled at all.
text data bss dec hex filename
2007 0 0 2007 7d7 kernel/rcu/srcu.oSize of arch/powerpc/boot/zImage changes from
text data bss dec hex filename
831552 64180 23944 919676 e087c arch/powerpc/boot/zImage : before
829504 64180 23952 917636 e0084 arch/powerpc/boot/zImage : afterso the savings are about ~2000 bytes.
Signed-off-by: Pranith Kumar
CC: Paul E. McKenney
CC: Josh Triplett
CC: Lai Jiangshan
Signed-off-by: Paul E. McKenney
[ paulmck: resolve conflict due to removal of arch/ia64/kvm/Kconfig. ]
24 Apr, 2014
1 commit
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Use NOKPROBE_SYMBOL macro to protect functions from
kprobes instead of __kprobes annotation in notifier.Signed-off-by: Masami Hiramatsu
Reviewed-by: Steven Rostedt
Reviewed-by: Josh Triplett
Cc: Paul E. McKenney
Link: http://lkml.kernel.org/r/20140417081835.26341.56128.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Ingo Molnar
26 Feb, 2014
1 commit
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(Trivial patch.)
If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded
to rcu_access_pointer(). This commit makes this downgrade in
__blocking_notifier_call_chain() which simply compares the RCU-protected
pointer against NULL with no dereferencing.Signed-off-by: Paul E. McKenney
Cc: Andrew Morton
Cc: Linus Torvalds
Reviewed-by: Josh Triplett
31 Oct, 2011
1 commit
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The changed files were only including linux/module.h for the
EXPORT_SYMBOL infrastructure, and nothing else. Revector them
onto the isolated export header for faster compile times.Nothing to see here but a whole lot of instances of:
-#include
+#includeThis commit is only changing the kernel dir; next targets
will probably be mm, fs, the arch dirs, etc.Signed-off-by: Paul Gortmaker
26 Jul, 2011
1 commit
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It is not necessary to share the same notifier.h.
This patch already moves register_reboot_notifier() and
unregister_reboot_notifier() from kernel/notifier.c to kernel/sys.c.[amwang@redhat.com: make allyesconfig succeed on ppc64]
Signed-off-by: WANG Cong
Cc: David Miller
Cc: "Rafael J. Wysocki"
Cc: Greg KH
Signed-off-by: WANG Cong
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
25 Feb, 2010
1 commit
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Update the rcu_dereference() usages to take advantage of the new
lockdep-based checking.Signed-off-by: Paul E. McKenney
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference:
[ -v2: fix allmodconfig missing symbol export build failure on x86 ]
Signed-off-by: Ingo Molnar
30 Aug, 2009
1 commit
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Add __kprobes to notify_die() because do_int3() calls notify_die()
instead of atomic_notify_call_chain() which is already marked as
__kprobes.Signed-off-by: Masami Hiramatsu
Acked-by: Ananth N Mavinakayanahalli
Cc: Ingo Molnar
LKML-Reference:
Signed-off-by: Frederic Weisbecker
25 Nov, 2008
1 commit
-
…ignal', 'core/urgent' and 'core/xen' into core/core
14 Oct, 2008
1 commit
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kprobes already has an extensive list of annotations for functions
that should not be instrumented. Add notrace annotations to these
functions as well.This is particularly useful for functions called by the NMI path.
Signed-off-by: Ingo Molnar
10 Sep, 2008
2 commits
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- unbreak ia64 (and powerpc) where function pointers dont
point at code but at data (reported by Tony Luck)[ mingo@elte.hu: various cleanups ]
Signed-off-by: Arjan van de Ven
Signed-off-by: Ingo Molnar -
during some development we suspected a case where we left something
in a notifier chain that was from a module that was unloaded already...
and that sort of thing is rather hard to track down.This patch adds a very simple sanity check (which isn't all that
expensive) to make sure the notifier we're about to call is
actually from either the kernel itself of from a still-loaded
module, avoiding a hard-to-chase-down crash.Signed-off-by: Arjan van de Ven
Signed-off-by: Ingo Molnar
29 Apr, 2008
1 commit
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The enhancement as asked for by Yasunori: if msgmni is set to a negative
value, register it back into the ipcns notifier chain.A new interface has been added to the notification mechanism:
notifier_chain_cond_register() registers a notifier block only if not already
registered. With that new interface we avoid taking care of the states
changes in procfs.Signed-off-by: Nadia Derbey
Cc: Yasunori Goto
Cc: Matt Helsley
Cc: Mingming Cao
Cc: Pierre Peiffer
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Feb, 2008
1 commit
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Every file should include the headers containing the prototypes for its global
functions (in this case {,un}register_reboot_notifier()).Signed-off-by: Adrian Bunk
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
20 Oct, 2007
1 commit
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There is separate notifier header, but no separate notifier .c file.
Extract notifier code out of kernel/sys.c which will remain for
misc syscalls I hope. Merge kernel/die_notifier.c into kernel/notifier.c.[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
