- 22 Aug, 2018 40 commits
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Chris Wilson authored
net_dim.h has a rather useful extension to BITS_PER_BYTE to compute the number of bits in a type (BITS_PER_BYTE * sizeof(T)), so promote the macro to bitops.h, alongside BITS_PER_BYTE, for wider usage. Link: http://lkml.kernel.org/r/20180706094458.14116-1-chris@chris-wilson.co.ukSigned-off-by:
Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:
Jani Nikula <jani.nikula@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andy Gospodarek <gospo@broadcom.com> Cc: David S. Miller <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Andy Shevchenko authored
nbits == 0 is safe to be supplied to the function body, so remove unnecessary checks in bitmap_to_arr32() and bitmap_from_arr32(). Link: http://lkml.kernel.org/r/20180531131914.44352-1-andriy.shevchenko@linux.intel.comSigned-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by:
Yury Norov <ynorov@caviumnetworks.com> Signed-off-by:
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Joe Perches authored
There is an external use case for multiple private MAINTAINER style files in a separate directory. Allow it. --mpath has a default of "./MAINTAINERS". The value entered can be either a file or a directory. The behaviors are now: --mpath <file> Read only the specific file as <MAINTAINER_TYPE> file --mpath <directory> Read all files in <directory> as <MAINTAINER_TYPE> files --mpath <directory> --find-maintainer-files Recurse through <directory> and read all files named MAINTAINERS Link: http://lkml.kernel.org/r/991b2f20112d53863cd79e61d908f1d26d3e1971.camel@perches.comSigned-off-by:Joe Perches <joe@perches.com> Tested-by:
Don Zickus <dzickus@redhat.com> Signed-off-by:
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Joe Perches authored
Add the ability to have an override for the location of the MAINTAINERS file. Miscellanea: o Properly indent a few lines with leading spaces Link: http://lkml.kernel.org/r/a86e69195076ed3c4c526fddc76b86c28e0a1e37.camel@perches.comSigned-off-by:
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Antonio Nino Diaz authored
Add option '--no-tree' to get_maintainer.pl script to allow using this script in projects that aren't the Linux kernel if they use the same format for their MAINTAINERS file. This command is also available in checkpatch.pl, for example. Link: http://lkml.kernel.org/r/04452ac6-1575-f612-72c6-6ea88e70a9d5@arm.comSigned-off-by:
Antonio Nino Diaz <antonio.ninodiaz@arm.com> Cc: Joe Perches <joe@perches.com> Signed-off-by:
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Davidlohr Bueso authored
Sprinkle lockdep_assert_irqs_enabled() checks in the functions that do not save and restore interrupts when dealing with the ep->wq.lock. These are ep_scan_ready_list() and those called by epoll_ctl(): ep_insert, ep_modify and ep_remove. [akpm@linux-foundation.org: remove too-obvious comments] Link: http://lkml.kernel.org/r/20180721183127.3busfa335zlcjeox@linux-r8p5Signed-off-by:
Davidlohr Bueso <dbueso@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
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Davidlohr Bueso authored
Both functions are similar to the context of ep_modify(), called via epoll_ctl(2). Just like ep_modify(), saving and restoring interrupts is an overkill in these calls as it will never be called with irqs disabled. While ep_remove() can be called directly from EPOLL_CTL_DEL, it can also be called when releasing the file, but this also complies with the above. Link: http://lkml.kernel.org/r/20180720172956.2883-3-dave@stgolabs.netSigned-off-by:
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Davidlohr Bueso authored
Patch series "fs/epoll: loosen irq safety when possible". Both patches replace saving+restoring interrupts when taking the ep->lock (now the waitqueue lock), with just disabling local irqs. This shows immediate performance benefits in patch 1 for an epoll workload running on Xen. The main concern we need to have with this sort of changes in epoll is the ep_poll_callback() which is passed to the wait queue wakeup and is done very often under irq context, this patch does not touch this call. Patches have been tested pretty heavily with the customer workload, microbenchmarks, ltp testcases and two high level workloads that use epoll under the hood: nginx and libevent benchmarks. This patch (of 2): Saving and restoring interrupts in ep_scan_ready_list() is an overkill as it is never called with interrupts disabled. Loosen this to simply disabling local irqs such that archs where managing irqs is expensive or virtual environments. This patch yields some throughput improvements on a workload that is epoll intensive running on a single Xen DomU. 1 Job 7500 --> 8800 enq/s (+17%) 2 Jobs 14000 --> 15200 enq/s (+8%) 3 Jobs 20500 --> 22300 enq/s (+8%) 4 Jobs 25000 --> 28000 enq/s (+8-12)% On bare metal: For a 2-socket 40-core (ht) IvyBridge on a few workloads, unfortunately I don't have a xen environment and the results for Xen I do have (which numbers are in patch 1) I don't have the actual workload, so cannot compare them directly. 1) Different configurations were used for a epoll_wait (pipes io) microbench (http://linux-scalability.org/epoll/epoll-test.c) and shows around a 7-10% improvement in overall total number of times the epoll_wait() loops when using both regular and nested epolls, so very raw numbers, but measurable nonetheless. # threads vanilla dirty 1 1677717 1805587 2 1660510 1854064 4 1610184 1805484 8 1577696 1751222 16 1568837 1725299 32 1291532 1378463 64 752584 787368 Note that stddev is pretty small. 2) Another pipe test, which shows no real measurable improvement. (http://www.xmailserver.org/linux-patches/pipetest.c) Link: http://lkml.kernel.org/r/20180720172956.2883-2-dave@stgolabs.netSigned-off-by:
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Christoph Hellwig authored
Better ensure we actually hold the lock using lockdep than just commenting on it. Due to the various exported _locked interfaces it is far too easy to get the locking wrong. Link: http://lkml.kernel.org/r/20171214152344.6880-4-hch@lst.deSigned-off-by:
Christoph Hellwig <hch@lst.de> Acked-by:
Ingo Molnar <mingo@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by:
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Matthew Wilcox authored
The userfaultfd code currently uses the unlocked waitqueue helpers for managing fault_wqh, but instead of holding the waitqueue lock for this waitqueue around these calls, it the waitqueue lock of fault_pending_wq, which is a different waitqueue instance. Given that the waitqueue is not exposed to the rest of the kernel this actually works ok at the moment, but prevents the userfaultfd locking rules from being enforced using lockdep. Switch to the internally locked waitqueue helpers instead. This means that the lock inside fault_wqh now nests inside the fault_pending_wqh lock, but that's not a problem since it was entirely unused before. [hch@lst.de: slight changelog updates] [rppt@linux.vnet.ibm.com: spotted changelog spellos] Link: http://lkml.kernel.org/r/20171214152344.6880-3-hch@lst.deSigned-off-by:
Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by:
Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by:
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Christoph Hellwig authored
Patch series "waitqueue lockdep annotation", v3. This series adds a strategic lockdep_assert_held to __wake_up_common to ensure callers really do hold the wait_queue_head lock when calling the unlocked wake_up variants. It turns out epoll did not do this for a fairly common path (hit all the time by systemd during bootup), so the second patch fixed this instance as well. This patch (of 3): The epoll code currently uses the unlocked waitqueue helpers for managing ep->wq, but instead of holding the waitqueue lock around these calls, it uses its own ep->lock spinlock. Given that the waitqueue is not exposed to the rest of the kernel this actually works ok at the moment, but prevents the epoll locking rules from being enforced using lockdep. Remove ep->lock and use the waitqueue lock to not only reduce the size of struct eventpoll but also to make sure we can assert locking invariants in the waitqueue code. Link: http://lkml.kernel.org/r/20171214152344.6880-2-hch@lst.deSigned-off-by:
Jason Baron <jbaron@akamai.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Jason Baron <jbaron@akamai.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by:
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Ard Biesheuvel authored
To avoid the need for relocating absolute references to tracepoint structures at boot time when running relocatable kernels (which may take a disproportionate amount of space), add the option to emit these tables as relative references instead. Link: http://lkml.kernel.org/r/20180704083651.24360-7-ard.biesheuvel@linaro.orgAcked-by:
Michael Ellerman <mpe@ellerman.id.au> Acked-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morris <james.morris@microsoft.com> Cc: James Morris <jmorris@namei.org> Cc: Jessica Yu <jeyu@kernel.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Nicolas Pitre <nico@linaro.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Russell King <linux@armlinux.org.uk> Cc: "Serge E. Hallyn" <serge@hallyn.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Thomas Garnier <thgarnie@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by:
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Ard Biesheuvel authored
Allow the PCI quirk tables to be emitted in a way that avoids absolute references to the hook functions. This reduces the size of the entries, and, more importantly, makes them invariant under runtime relocation (e.g., for KASLR) Link: http://lkml.kernel.org/r/20180704083651.24360-6-ard.biesheuvel@linaro.orgAcked-by:
Bjorn Helgaas <bhelgaas@google.com> Acked-by:
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Ard Biesheuvel authored
Allow the initcall tables to be emitted using relative references that are only half the size on 64-bit architectures and don't require fixups at runtime on relocatable kernels. Link: http://lkml.kernel.org/r/20180704083651.24360-5-ard.biesheuvel@linaro.orgAcked-by:
James Morris <james.morris@microsoft.com> Acked-by:
Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by:
Petr Mladek <pmladek@suse.com> Acked-by:
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Ard Biesheuvel authored
An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab entries, each consisting of two 64-bit fields containing absolute references, to the symbol itself and to a char array containing its name, respectively. When we build the same configuration with KASLR enabled, we end up with an additional ~192 KB of relocations in the .init section, i.e., one 24 byte entry for each absolute reference, which all need to be processed at boot time. Given how the struct kernel_symbol that describes each entry is completely local to module.c (except for the references emitted by EXPORT_SYMBOL() itself), we can easily modify it to contain two 32-bit relative references instead. This reduces the size of the __ksymtab section by 50% for all 64-bit architectures, and gets rid of the runtime relocations entirely for architectures implementing KASLR, either via standard PIE linking (arm64) or using custom host tools (x86). Note that the binary search involving __ksymtab contents relies on each section being sorted by symbol name. This is implemented based on the input section names, not the names in the ksymtab entries, so this patch does not interfere with that. Given that the use of place-relative relocations requires support both in the toolchain and in the module loader, we cannot enable this feature for all architectures. So make it dependent on whether CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined. Link: http://lkml.kernel.org/r/20180704083651.24360-4-ard.biesheuvel@linaro.orgSigned-off-by:
Jessica Yu <jeyu@kernel.org> Acked-by:
Will Deacon <will.deacon@arm.com> Acked-by:
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Ard Biesheuvel authored
To allow existing C code to be incorporated into the decompressor or the UEFI stub, introduce a CPP macro that turns all EXPORT_SYMBOL_xxx declarations into nops, and #define it in places where such exports are undesirable. Note that this gets rid of a rather dodgy redefine of linux/export.h's header guard. Link: http://lkml.kernel.org/r/20180704083651.24360-3-ard.biesheuvel@linaro.orgSigned-off-by:
Nicolas Pitre <nico@linaro.org> Acked-by:
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Ard Biesheuvel authored
Patch series "add support for relative references in special sections", v10. This adds support for emitting special sections such as initcall arrays, PCI fixups and tracepoints as relative references rather than absolute references. This reduces the size by 50% on 64-bit architectures, but more importantly, it removes the need for carrying relocation metadata for these sections in relocatable kernels (e.g., for KASLR) that needs to be fixed up at boot time. On arm64, this reduces the vmlinux footprint of such a reference by 8x (8 byte absolute reference + 24 byte RELA entry vs 4 byte relative reference) Patch #3 was sent out before as a single patch. This series supersedes the previous submission. This version makes relative ksymtab entries dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather than trying to infer from kbuild test robot replies for which architectures it should be blacklisted. Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS, and sets it for the main architectures that are expected to benefit the most from this feature, i.e., 64-bit architectures or ones that use runtime relocations. Patch #2 add support for #define'ing __DISABLE_EXPORTS to get rid of ksymtab/kcrctab sections in decompressor and EFI stub objects when rebuilding existing C files to run in a different context. Patches #4 - #6 implement relative references for initcalls, PCI fixups and tracepoints, respectively, all of which produce sections with order ~1000 entries on an arm64 defconfig kernel with tracing enabled. This means we save about 28 KB of vmlinux space for each of these patches. [From the v7 series blurb, which included the jump_label patches as well]: For the arm64 kernel, all patches combined reduce the memory footprint of vmlinux by about 1.3 MB (using a config copied from Ubuntu that has KASLR enabled), of which ~1 MB is the size reduction of the RELA section in .init, and the remaining 300 KB is reduction of .text/.data. This patch (of 6): Before updating certain subsystems to use place relative 32-bit relocations in special sections, to save space and reduce the number of absolute relocations that need to be processed at runtime by relocatable kernels, introduce the Kconfig symbol and define it for some architectures that should be able to support and benefit from it. Link: http://lkml.kernel.org/r/20180704083651.24360-2-ard.biesheuvel@linaro.orgSigned-off-by:
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Colin Ian King authored
Here are some of the more common spelling mistakes and typos that I've found while fixing up spelling mistakes in the kernel over the past 6 months. Link: http://lkml.kernel.org/r/20180629150603.1159-1-colin.king@canonical.comSigned-off-by:
Colin Ian King <colin.king@canonical.com> Cc: Joe Perches <joe@perches.com> Signed-off-by:
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Dmitry Vyukov authored
Currently task hung checking interval is equal to timeout, as the result hung is detected anywhere between timeout and 2*timeout. This is fine for most interactive environments, but this hurts automated testing setups (syzbot). In an automated setup we need to strictly order CPU lockup < RCU stall < workqueue lockup < task hung < silent loss, so that RCU stall is not detected as task hung and task hung is not detected as silent machine loss. The large variance in task hung detection timeout requires setting silent machine loss timeout to a very large value (e.g. if task hung is 3 mins, then silent loss need to be set to ~7 mins). The additional 3 minutes significantly reduce testing efficiency because usually we crash kernel within a minute, and this can add hours to bug localization process as it needs to do dozens of tests. Allow setting checking interval separately from timeout. This allows to set timeout to, say, 3 minutes, but checking interval to 10 secs. The interval is controlled via a new hung_task_check_interval_secs sysctl, similar to the existing hung_task_timeout_secs sysctl. The default value of 0 results in the current behavior: checking interval is equal to timeout. [akpm@linux-foundation.org: update hung_task_timeout_max's comment] Link: http://lkml.kernel.org/r/20180611111004.203513-1-dvyukov@google.comSigned-off-by:
Dmitry Vyukov <dvyukov@google.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
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Arnd Bergmann authored
The get_seconds() call returns a 32-bit timestamp on some architectures, and will overflow in the future. The newer ktime_get_real_seconds() always returns a 64-bit timestamp that does not suffer from this problem. Link: http://lkml.kernel.org/r/20180618150329.941903-1-arnd@arndb.deSigned-off-by:
Arnd Bergmann <arnd@arndb.de> Reviewed-by:
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Rasmus Villemoes authored
Appararently, it's possible to have a non-trivial TU include a few headers, including linux/build_bug.h, without ending up with linux/types.h. So the 0day bot sent me config: um-x86_64_defconfig (attached as .config) >> include/linux/compiler.h:316:3: error: unknown type name 'bool'; did you mean '_Bool'? bool __cond = !(condition); \ for something I'm working on. Rather than contributing to the #include madness and including linux/types.h from compiler.h, just use int. Link: http://lkml.kernel.org/r/20180817101036.20969-1-linux@rasmusvillemoes.dkSigned-off-by:Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Christopher Li <sparse@chrisli.org> Signed-off-by:
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Anna-Maria Gleixner authored
The irqsave variant of refcount_dec_and_lock handles irqsave/restore when taking/releasing the spin lock. With this variant the call of local_irq_save/restore is no longer required. [bigeasy@linutronix.de: s@atomic_dec_and_lock@refcount_dec_and_lock@g] Link: http://lkml.kernel.org/r/20180703200141.28415-7-bigeasy@linutronix.deSigned-off-by:
Anna-Maria Gleixner <anna-maria@linutronix.de> Signed-off-by:
Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Sebastian Andrzej Siewior authored
refcount_t type and corresponding API should be used instead of atomic_t wh en the variable is used as a reference counter. This avoids accidental refcounter overflows that might lead to use-after-free situations. Link: http://lkml.kernel.org/r/20180703200141.28415-6-bigeasy@linutronix.deSigned-off-by:
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Anna-Maria Gleixner authored
The irqsave variant of refcount_dec_and_lock handles irqsave/restore when taking/releasing the spin lock. With this variant the call of local_irq_save/restore is no longer required. [bigeasy@linutronix.de: s@atomic_dec_and_lock@refcount_dec_and_lock@g] Link: http://lkml.kernel.org/r/20180703200141.28415-5-bigeasy@linutronix.deSigned-off-by:
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Sebastian Andrzej Siewior authored
refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This permits avoiding accidental refcounter overflows that might lead to use-after-free situations. Link: http://lkml.kernel.org/r/20180703200141.28415-4-bigeasy@linutronix.deSigned-off-by:
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Kees Cook authored
Things like 3619dec5 ("dh key: fix rounding up KDF output length") expose the lack of explicit documentation for roundup() vs round_up(). At least we can try to document it better if anyone goes looking. Link: http://lkml.kernel.org/r/20180703041950.GA43464@beastSigned-off-by:
Kees Cook <keescook@chromium.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by:
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Dmitry Vyukov authored
Explicitly state that WARN*() should be used only for recoverable kernel issues/bugs and that it should not be used for any kind of invalid external inputs or transient conditions. Motivation: it's a very useful capability to be able to understand if a particular kernel splat means a kernel bug or simply an invalid user-space program. For the former one wants to notify kernel developers, while notifying kernel developers for the latter is annoying. Even a kernel developer may not know what to do with a WARNING in an unfamiliar subsystem. This is especially critical for any automated testing systems that may use panic_on_warn and mail kernel developers. The clear separation also serves as an additional documentation: is it a condition that must never occur because of additional checks/logic elsewhere? or is it simply a check for invalid inputs or unfortunate conditions? Use of pr_err() for user messages also leads to better error messages. "Something is wrong in file foo on line X" is not particularly useful message for end user. pr_err() forces developers to write more meaningful error messages for user. As of now we are almost there. We are doing systematic kernel testing with panic_on_warn and are not seeing massive amounts of false positives. But every now and then another WARN on ENOMEM or invalid inputs pops up and leads to a lengthy argument each time. The goal of this change is to officially document the rules. Link: http://lkml.kernel.org/r/20180620103716.61636-1-dvyukov@gmail.comSigned-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Omar Sandoval authored
The vmcoreinfo information is useful for runtime debugging tools, not just for crash dumps. A lot of this information can be determined by other means, but this is much more convenient, and it only adds a page at most to the file. Link: http://lkml.kernel.org/r/fddbcd08eed76344863303878b12de1c1e2a04b6.1531953780.git.osandov@fb.comSigned-off-by:
Omar Sandoval <osandov@fb.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: James Morse <james.morse@arm.com> Signed-off-by:
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Omar Sandoval authored
This is preparation for allowing CRASH_CORE to be enabled for any architecture. swapper_pg_dir is always either an array or a macro expanding to NULL. In the latter case, VMCOREINFO_SYMBOL() won't work, as it tries to take the address of the given symbol: #define VMCOREINFO_SYMBOL(name) \ vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name) Instead, use VMCOREINFO_SYMBOL_ARRAY(), which uses the value: #define VMCOREINFO_SYMBOL_ARRAY(name) \ vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)name) This is the same thing for the array case but isn't an error for the macro case. Link: http://lkml.kernel.org/r/c05f9781ec204f40fc96f95086e7b6de6a3eb2c3.1532563124.git.osandov@fb.comSigned-off-by: -
Omar Sandoval authored
The current code does a full search of the segment list every time for every page. This is wasteful, since it's almost certain that the next page will be in the same segment. Instead, check if the previous segment covers the current page before doing the list search. Link: http://lkml.kernel.org/r/fd346c11090cf93d867e01b8d73a6567c5ac6361.1531953780.git.osandov@fb.comSigned-off-by:
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Omar Sandoval authored
Currently, the ELF file header, program headers, and note segment are allocated all at once, in some icky code dating back to 2.3. Programs tend to read the file header, then the program headers, then the note segment, all separately, so this is a waste of effort. It's cleaner and more efficient to handle the three separately. Link: http://lkml.kernel.org/r/19c92cbad0e11f6103ff3274b2e7a7e51a1eb74b.1531953780.git.osandov@fb.comSigned-off-by:
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Omar Sandoval authored
Now that we're using an rwsem, we can hold it during the entirety of read_kcore() and have a common return path. This is preparation for the next change. [akpm@linux-foundation.org: fix locking bug reported by Tetsuo Handa] Link: http://lkml.kernel.org/r/d7cfbc1e8a76616f3b699eaff9df0a2730380534.1531953780.git.osandov@fb.comSigned-off-by:
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Omar Sandoval authored
There's a theoretical race condition that will cause /proc/kcore to miss a memory hotplug event: CPU0 CPU1 // hotplug event 1 kcore_need_update = 1 open_kcore() open_kcore() kcore_update_ram() kcore_update_ram() // Walk RAM // Walk RAM __kcore_update_ram() __kcore_update_ram() kcore_need_update = 0 // hotplug event 2 kcore_need_update = 1 kcore_need_update = 0 Note that CPU1 set up the RAM kcore entries with the state after hotplug event 1 but cleared the flag for hotplug event 2. The RAM entries will therefore be stale until there is another hotplug event. This is an extremely unlikely sequence of events, but the fix makes the synchronization saner, anyways: we serialize the entire update sequence, which means that whoever clears the flag will always succeed in replacing the kcore list. Link: http://lkml.kernel.org/r/6106c509998779730c12400c1b996425df7d7089.1531953780.git.osandov@fb.comSigned-off-by: -
Omar Sandoval authored
Now we only need kclist_lock from user context and at fs init time, and the following changes need to sleep while holding the kclist_lock. Link: http://lkml.kernel.org/r/521ba449ebe921d905177410fee9222d07882f0d.1531953780.git.osandov@fb.comSigned-off-by:
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Omar Sandoval authored
The memory hotplug notifier kcore_callback() only needs kclist_lock to prevent races with __kcore_update_ram(), but we can easily eliminate that race by using an atomic xchg() in __kcore_update_ram(). This is preparation for converting kclist_lock to an rwsem. Link: http://lkml.kernel.org/r/0a4bc89f4dbde8b5b2ea309f7b4fb6a85fe29df2.1531953780.git.osandov@fb.comSigned-off-by:
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Omar Sandoval authored
Patch series "/proc/kcore improvements", v4. This series makes a few improvements to /proc/kcore. It fixes a couple of small issues in v3 but is otherwise the same. Patches 1, 2, and 3 are prep patches. Patch 4 is a fix/cleanup. Patch 5 is another prep patch. Patches 6 and 7 are optimizations to ->read(). Patch 8 makes it possible to enable CRASH_CORE on any architecture, which is needed for patch 9. Patch 9 adds vmcoreinfo to /proc/kcore. This patch (of 9): kclist_add() is only called at init time, so there's no point in grabbing any locks. We're also going to replace the rwlock with a rwsem, which we don't want to try grabbing during early boot. While we're here, mark kclist_add() with __init so that we'll get a warning if it's called from non-init code. Link: http://lkml.kernel.org/r/98208db1faf167aa8b08eebfa968d95c70527739.1531953780.git.osandov@fb.comSigned-off-by:
Bhupesh Sharma <bhsharma@redhat.com> Tested-by:
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James Morse authored
elf_kcore_store_hdr() uses __pa() to find the physical address of KCORE_RAM or KCORE_TEXT entries exported as program headers. This trips CONFIG_DEBUG_VIRTUAL's checks, as the KCORE_TEXT entries are not in the linear map. Handle these two cases separately, using __pa_symbol() for the KCORE_TEXT entries. Link: http://lkml.kernel.org/r/20180711131944.15252-1-james.morse@arm.comSigned-off-by:
James Morse <james.morse@arm.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by:
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Souptick Joarder authored
Use new return type vm_fault_t for fault handler in struct vm_operations_struct. For now, this is just documenting that the function returns a VM_FAULT value rather than an errno. Once all instances are converted, vm_fault_t will become a distinct type. See 1c8f4220 ("mm: change return type to vm_fault_t") for reference. Link: http://lkml.kernel.org/r/20180702153325.GA3875@jordon-HP-15-Notebook-PCSigned-off-by:
Souptick Joarder <jrdr.linux@gmail.com> Reviewed-by:
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Alexey Dobriyan authored
Number of CPUs is never high enough to force 64-bit arithmetic. Save couple of bytes on x86_64. Link: http://lkml.kernel.org/r/20180627200710.GC18434@avx2Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Reviewed-by:
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Alexey Dobriyan authored
Link: http://lkml.kernel.org/r/20180627200614.GB18434@avx2Signed-off-by:
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