Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.
This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.
There are a variety of indentation styles found.
a) 4 spaces + '---help---'
b) 7 spaces + '---help---'
c) 8 spaces + '---help---'
d) 1 space + 1 tab + '---help---'
e) 1 tab + '---help---' (correct indentation)
f) 1 tab + 1 space + '---help---'
g) 1 tab + 2 spaces + '---help---'
In order to convert all of them to 1 tab + 'help', I ran the
following commend:
$ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Pull UML updates from Richard Weinberger:
- Use fdatasync() in ubd
- Add a generic "fd" vector transport
- Minor cleanups and fixes
* tag 'for-linus-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: virtio: Replace zero-length array with flexible-array
um: Use fdatasync() when mapping the UBD FSYNC command
um: Do not evaluate compiler's library path when cleaning
um: Neaten vu_err macro definition
um: Add a generic "fd" vector transport
um: Add include: memset() and memcpy() are in <string.h>
Except for historical confusion in the kprobes/uprobes and bpf tracers,
which has been fixed now, there is no good reason to ever allow user
memory accesses from probe_kernel_read. Switch probe_kernel_read to only
read from kernel memory.
[akpm@linux-foundation.org: update it for "mm, dump_page(): do not crash with invalid mapping pointer"]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-17-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently architectures have to override every routine that probes
kernel memory, which includes a pure read and strcpy, both in strict
and not strict variants. Just provide a single arch hooks instead to
make sure all architectures cover all the cases.
[akpm@linux-foundation.org: fix !CONFIG_X86_64 build]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200521152301.2587579-11-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The powerpc 32-bit implementation of pgtable has nice shortcuts for
accessing kernel PMD and PTE for a given virtual address. Make these
helpers available for all architectures.
[rppt@linux.ibm.com: microblaze: fix page table traversal in setup_rt_frame()]
Link: http://lkml.kernel.org/r/20200518191511.GD1118872@kernel.org
[akpm@linux-foundation.org: s/pmd_ptr_k/pmd_off_k/ in various powerpc places]
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200514170327.31389-9-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).
Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages. And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.
Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers. Also, it will consolidate
printings with headers.
Introduce show_stack_loglvl(), that eventually will substitute
show_stack().
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Link: http://lkml.kernel.org/r/20200418201944.482088-37-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull Kbuild updates from Masahiro Yamada:
- fix warnings in 'make clean' for ARCH=um, hexagon, h8300, unicore32
- ensure to rebuild all objects when the compiler is upgraded
- exclude system headers from dependency tracking and fixdep processing
- fix potential bit-size mismatch between the kernel and BPF user-mode
helper
- add the new syntax 'userprogs' to build user-space programs for the
target architecture (the same arch as the kernel)
- compile user-space sample code under samples/ for the target arch
instead of the host arch
- make headers_install fail if a CONFIG option is leaked to user-space
- sanitize the output format of scripts/checkstack.pl
- handle ARM 'push' instruction in scripts/checkstack.pl
- error out before modpost if a module name conflict is found
- error out when multiple directories are passed to M= because this
feature is broken for a long time
- add CONFIG_DEBUG_INFO_COMPRESSED to support compressed debug info
- a lot of cleanups of modpost
- dump vmlinux symbols out into vmlinux.symvers, and reuse it in the
second pass of modpost
- do not run the second pass of modpost if nothing in modules is
updated
- install modules.builtin(.modinfo) by 'make install' as well as by
'make modules_install' because it is useful even when
CONFIG_MODULES=n
- add new command line variables, GZIP, BZIP2, LZOP, LZMA, LZ4, and XZ
to allow users to use alternatives such as pigz, pbzip2, etc.
* tag 'kbuild-v5.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (96 commits)
kbuild: add variables for compression tools
Makefile: install modules.builtin even if CONFIG_MODULES=n
mksysmap: Fix the mismatch of '.L' symbols in System.map
kbuild: doc: rename LDFLAGS to KBUILD_LDFLAGS
modpost: change elf_info->size to size_t
modpost: remove is_vmlinux() helper
modpost: strip .o from modname before calling new_module()
modpost: set have_vmlinux in new_module()
modpost: remove mod->skip struct member
modpost: add mod->is_vmlinux struct member
modpost: remove is_vmlinux() call in check_for_{gpl_usage,unused}()
modpost: remove mod->is_dot_o struct member
modpost: move -d option in scripts/Makefile.modpost
modpost: remove -s option
modpost: remove get_next_text() and make {grab,release_}file static
modpost: use read_text_file() and get_line() for reading text files
modpost: avoid false-positive file open error
modpost: fix potential mmap'ed file overrun in get_src_version()
modpost: add read_text_file() and get_line() helpers
modpost: do not call get_modinfo() for vmlinux(.o)
...
Pull livepatching updates from Jiri Kosina:
- simplifications and improvements for issues Peter Ziljstra found
during his previous work on W^X cleanups.
This allows us to remove livepatch arch-specific .klp.arch sections
and add proper support for jump labels in patched code.
Also, this patchset removes the last module_disable_ro() usage in the
tree.
Patches from Josh Poimboeuf and Peter Zijlstra
- a few other minor cleanups
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/livepatching/livepatching:
MAINTAINERS: add lib/livepatch to LIVE PATCHING
livepatch: add arch-specific headers to MAINTAINERS
livepatch: Make klp_apply_object_relocs static
MAINTAINERS: adjust to livepatch .klp.arch removal
module: Make module_enable_ro() static again
x86/module: Use text_mutex in apply_relocate_add()
module: Remove module_disable_ro()
livepatch: Remove module_disable_ro() usage
x86/module: Use text_poke() for late relocations
s390/module: Use s390_kernel_write() for late relocations
s390: Change s390_kernel_write() return type to match memcpy()
livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols
livepatch: Remove .klp.arch
livepatch: Apply vmlinux-specific KLP relocations early
livepatch: Disallow vmlinux.ko
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
We do not need to update the metadata (atime, mtime, etc)
on the UBD file and/or the COW file until UML exits.
UBD image mtime is checked in UML only when opening
the files. After that they are locked and used
exclusively by a single UML instance, so there is
no point wasting resources on updating metadata on
every sync. We can sync data only. The host will
always update mtime if a file has been modified upon
closing it.
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Since commit a83e4ca26a ("kbuild: remove cc-option switch from
-Wframe-larger-than="), 'make ARCH=um clean' emits an error message
as follows:
$ make ARCH=um clean
gcc: error: missing argument to '-Wframe-larger-than='
We do not care compiler flags when cleaning.
Use the '=' operator for lazy expansion because we do not use
LDFLAGS_pcap.o or LDFLAGS_vde.o when cleaning.
While I was here, I removed the redundant -r option because it
already exists in the recipe.
Fixes: a83e4ca26a ("kbuild: remove cc-option switch from -Wframe-larger-than=")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com> [build]
Signed-off-by: Richard Weinberger <richard@nod.at>
Defining a macro with ... and __VA_ARGS__ (without ##) can cause
compilation errors if a macro use does not have additional args.
Add ## to __VA_ARGS__ in the macro definition.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Learn to take a pre-opened file-descriptor for vector IO.
Instead of teaching the driver to open a FD in multiple ways, it can
rely on management layer to do it on its behalf. For example, this
allows inheriting a preconfigured device fd or a simple socketpair()
setup, without further arguments, privileges or system access by UML.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
These two functions are otherwise unknown to the pedantic compiler.
Include the correct header to enable the build to succeed.
Signed-off-by: Zach van Rijn <me@zv.io>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Merge {CLEAN,MRPROPER,DISTCLEAN}_DIRS into {CLEAN,MRPROPER,DISTCLEAN}_FILES
because the difference is just the -r option passed to the 'rm' command.
Do likewise as commit 1634f2bfdb ("kbuild: remove clean-dirs syntax").
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Since commit a83e4ca26a ("kbuild: remove cc-option switch from
-Wframe-larger-than="), 'make ARCH=um clean' emits an error message
as follows:
$ make ARCH=um clean
gcc: error: missing argument to '-Wframe-larger-than='
We do not care compiler flags when cleaning.
Use the '=' operator for lazy expansion because we do not use
LDFLAGS_pcap.o or LDFLAGS_vde.o when cleaning.
While I was here, I removed the redundant -r option because it
already exists in the recipe.
Fixes: a83e4ca26a ("kbuild: remove cc-option switch from -Wframe-larger-than=")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Tested-by: Nathan Chancellor <natechancellor@gmail.com> [build]
Because of late module patching, a livepatch module needs to be able to
apply some of its relocations well after it has been loaded. Instead of
playing games with module_{dis,en}able_ro(), use existing text poking
mechanisms to apply relocations after module loading.
So far only x86, s390 and Power have HAVE_LIVEPATCH but only the first
two also have STRICT_MODULE_RWX.
This will allow removal of the last module_disable_ro() usage in
livepatch. The ultimate goal is to completely disallow making
executable mappings writable.
[ jpoimboe: Split up patches. Use mod state to determine whether
memcpy() can be used. Implement text_poke() for UML. ]
Cc: x86@kernel.org
Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
No big problem as "raw" and "gre" have the same length, but could go wrong if
they don't in the future.
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Without CONFIG_SECCOMP, we don't get this include recursively
through the existing includes, thus failing the build on not
having __NR_syscall_max defined. Add the necessary include to
fix this.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Two independent changes here ended up going into the tree
one after another, without a necessary rename, fix that.
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Fixes: f185063bff ("um: Move timer-internal.h to non-shared")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Pull UML updates from Richard Weinberger:
- New mode for time travel, external via virtio
- Fixes for ubd to make sure no requests can get lost
- Fixes for vector networking
- Allow CONFIG_STATIC_LINK only when possible
- Minor cleanups and fixes
* tag 'for-linus-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Remove some unnecessary NULL checks in vector_user.c
um: vector: Avoid NULL ptr deference if transport is unset
um: Make CONFIG_STATIC_LINK actually static
um: Implement cpu_relax() as ndelay(1) for time-travel
um: Implement ndelay/udelay in time-travel mode
um: Implement time-travel=ext
um: virtio: Implement VHOST_USER_PROTOCOL_F_INBAND_NOTIFICATIONS
um: time-travel: Rewrite as an event scheduler
um: Move timer-internal.h to non-shared
hostfs: Use kasprintf() instead of fixed buffer formatting
um: falloc.h needs to be directly included for older libc
um: ubd: Retry buffer read on any kind of error
um: ubd: Prevent buffer overrun on command completion
um: Fix overlapping ELF segments when statically linked
um: Delete never executed timer
um: Don't overwrite ethtool driver version
um: Fix len of file in create_pid_file
um: Don't use console_drivers directly
um: Cleanup CONFIG_IOSCHED_CFQ
Pull char/misc driver updates from Greg KH:
"Here is the big set of char/misc/other driver patches for 5.7-rc1.
Lots of things in here, and it's later than expected due to some
reverts to resolve some reported issues. All is now clean with no
reported problems in linux-next.
Included in here is:
- interconnect updates
- mei driver updates
- uio updates
- nvmem driver updates
- soundwire updates
- binderfs updates
- coresight updates
- habanalabs updates
- mhi new bus type and core
- extcon driver updates
- some Kconfig cleanups
- other small misc driver cleanups and updates
As mentioned, all have been in linux-next for a while, and with the
last two reverts, all is calm and good"
* tag 'char-misc-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (174 commits)
Revert "driver core: platform: Initialize dma_parms for platform devices"
Revert "amba: Initialize dma_parms for amba devices"
amba: Initialize dma_parms for amba devices
driver core: platform: Initialize dma_parms for platform devices
bus: mhi: core: Drop the references to mhi_dev in mhi_destroy_device()
bus: mhi: core: Initialize bhie field in mhi_cntrl for RDDM capture
bus: mhi: core: Add support for reading MHI info from device
misc: rtsx: set correct pcr_ops for rts522A
speakup: misc: Use dynamic minor numbers for speakup devices
mei: me: add cedar fork device ids
coresight: do not use the BIT() macro in the UAPI header
Documentation: provide IBM contacts for embargoed hardware
nvmem: core: remove nvmem_sysfs_get_groups()
nvmem: core: use is_bin_visible for permissions
nvmem: core: use device_register and device_unregister
nvmem: core: add root_only member to nvmem device struct
extcon: axp288: Add wakeup support
extcon: Mark extcon_get_edev_name() function as exported symbol
extcon: palmas: Hide error messages if gpio returns -EPROBE_DEFER
dt-bindings: extcon: usbc-cros-ec: convert extcon-usbc-cros-ec.txt to yaml format
...
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
Merge updates from Andrew Morton:
"A large amount of MM, plenty more to come.
Subsystems affected by this patch series:
- tools
- kthread
- kbuild
- scripts
- ocfs2
- vfs
- mm: slub, kmemleak, pagecache, gup, swap, memcg, pagemap, mremap,
sparsemem, kasan, pagealloc, vmscan, compaction, mempolicy,
hugetlbfs, hugetlb"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (155 commits)
include/linux/huge_mm.h: check PageTail in hpage_nr_pages even when !THP
mm/hugetlb: fix build failure with HUGETLB_PAGE but not HUGEBTLBFS
selftests/vm: fix map_hugetlb length used for testing read and write
mm/hugetlb: remove unnecessary memory fetch in PageHeadHuge()
mm/hugetlb.c: clean code by removing unnecessary initialization
hugetlb_cgroup: add hugetlb_cgroup reservation docs
hugetlb_cgroup: add hugetlb_cgroup reservation tests
hugetlb: support file_region coalescing again
hugetlb_cgroup: support noreserve mappings
hugetlb_cgroup: add accounting for shared mappings
hugetlb: disable region_add file_region coalescing
hugetlb_cgroup: add reservation accounting for private mappings
mm/hugetlb_cgroup: fix hugetlb_cgroup migration
hugetlb_cgroup: add interface for charge/uncharge hugetlb reservations
hugetlb_cgroup: add hugetlb_cgroup reservation counter
hugetlbfs: Use i_mmap_rwsem to address page fault/truncate race
hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
mm/memblock.c: remove redundant assignment to variable max_addr
mm: mempolicy: require at least one nodeid for MPOL_PREFERRED
mm: mempolicy: use VM_BUG_ON_VMA in queue_pages_test_walk()
...
Pull exec/proc updates from Eric Biederman:
"This contains two significant pieces of work: the work to sort out
proc_flush_task, and the work to solve a deadlock between strace and
exec.
Fixing proc_flush_task so that it no longer requires a persistent
mount makes improvements to proc possible. The removal of the
persistent mount solves an old regression that that caused the hidepid
mount option to only work on remount not on mount. The regression was
found and reported by the Android folks. This further allows Alexey
Gladkov's work making proc mount options specific to an individual
mount of proc to move forward.
The work on exec starts solving a long standing issue with exec that
it takes mutexes of blocking userspace applications, which makes exec
extremely deadlock prone. For the moment this adds a second mutex with
a narrower scope that handles all of the easy cases. Which makes the
tricky cases easy to spot. With a little luck the code to solve those
deadlocks will be ready by next merge window"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (25 commits)
signal: Extend exec_id to 64bits
pidfd: Use new infrastructure to fix deadlocks in execve
perf: Use new infrastructure to fix deadlocks in execve
proc: io_accounting: Use new infrastructure to fix deadlocks in execve
proc: Use new infrastructure to fix deadlocks in execve
kernel/kcmp.c: Use new infrastructure to fix deadlocks in execve
kernel: doc: remove outdated comment cred.c
mm: docs: Fix a comment in process_vm_rw_core
selftests/ptrace: add test cases for dead-locks
exec: Fix a deadlock in strace
exec: Add exec_update_mutex to replace cred_guard_mutex
exec: Move exec_mmap right after de_thread in flush_old_exec
exec: Move cleanup of posix timers on exec out of de_thread
exec: Factor unshare_sighand out of de_thread and call it separately
exec: Only compute current once in flush_old_exec
pid: Improve the comment about waiting in zap_pid_ns_processes
proc: Remove the now unnecessary internal mount of proc
uml: Create a private mount of proc for mconsole
uml: Don't consult current to find the proc_mnt in mconsole_proc
proc: Use a list of inodes to flush from proc
...
The idea comes from a discussion between Linus and Andrea [1].
Before this patch we only allow a page fault to retry once. We achieved
this by clearing the FAULT_FLAG_ALLOW_RETRY flag when doing
handle_mm_fault() the second time. This was majorly used to avoid
unexpected starvation of the system by looping over forever to handle the
page fault on a single page. However that should hardly happen, and after
all for each code path to return a VM_FAULT_RETRY we'll first wait for a
condition (during which time we should possibly yield the cpu) to happen
before VM_FAULT_RETRY is really returned.
This patch removes the restriction by keeping the FAULT_FLAG_ALLOW_RETRY
flag when we receive VM_FAULT_RETRY. It means that the page fault handler
now can retry the page fault for multiple times if necessary without the
need to generate another page fault event. Meanwhile we still keep the
FAULT_FLAG_TRIED flag so page fault handler can still identify whether a
page fault is the first attempt or not.
Then we'll have these combinations of fault flags (only considering
ALLOW_RETRY flag and TRIED flag):
- ALLOW_RETRY and !TRIED: this means the page fault allows to
retry, and this is the first try
- ALLOW_RETRY and TRIED: this means the page fault allows to
retry, and this is not the first try
- !ALLOW_RETRY and !TRIED: this means the page fault does not allow
to retry at all
- !ALLOW_RETRY and TRIED: this is forbidden and should never be used
In existing code we have multiple places that has taken special care of
the first condition above by checking against (fault_flags &
FAULT_FLAG_ALLOW_RETRY). This patch introduces a simple helper to detect
the first retry of a page fault by checking against both (fault_flags &
FAULT_FLAG_ALLOW_RETRY) and !(fault_flag & FAULT_FLAG_TRIED) because now
even the 2nd try will have the ALLOW_RETRY set, then use that helper in
all existing special paths. One example is in __lock_page_or_retry(), now
we'll drop the mmap_sem only in the first attempt of page fault and we'll
keep it in follow up retries, so old locking behavior will be retained.
This will be a nice enhancement for current code [2] at the same time a
supporting material for the future userfaultfd-writeprotect work, since in
that work there will always be an explicit userfault writeprotect retry
for protected pages, and if that cannot resolve the page fault (e.g., when
userfaultfd-writeprotect is used in conjunction with swapped pages) then
we'll possibly need a 3rd retry of the page fault. It might also benefit
other potential users who will have similar requirement like userfault
write-protection.
GUP code is not touched yet and will be covered in follow up patch.
Please read the thread below for more information.
[1] https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/
[2] https://lore.kernel.org/lkml/20181230154648.GB9832@redhat.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160246.9790-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kfree() already checks for null pointers, so additional checking is
unnecessary.
Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
In external or inf-cpu time-travel mode, ndelay/udelay currently
just waste CPU time since the simulation time doesn't advance.
Implement them properly in this case.
Note that the "if (time_travel_mode == ...)" parts compile out
if CONFIG_UML_TIME_TRAVEL_SUPPORT isn't set, time_travel_mode is
defined to TT_MODE_OFF in that case.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This implements synchronized time-travel mode which - using a special
application on a unix socket - lets multiple machines take part in a
time-travelling simulation together.
The protocol for the unix domain socket is defined in the new file
include/uapi/linux/um_timetravel.h.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Implement in-band notifications that are necessary for running
vhost-user devices under externally synchronized time-travel
mode (which is in a follow-up patch). This feature makes what
usually should be eventfd notifications in-band messages.
We'll prefer this feature, under the assumption that only a
few (simulation) devices will ever support it, since it's not
very efficient.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Instead of tracking all the various timer configurations,
modify the time-travel mode to have an event scheduler and
use a timer event on the scheduler to handle the different
timer configurations.
This doesn't change the function right now, but it prepares
the code for having different kinds of events in the future
(i.e. interrupts coming from other devices that are part of
co-simulation.)
While at it, also move time_travel_sleep() to time.c to
reduce the externally visible API surface.
Also, we really should mark time-travel as incompatible with
SMP, even if UML doesn't support SMP yet.
Finally, I noticed a bug while developing this - if we move
time forward due to consuming time while reading the clock,
we might move across the next event and that would cause us
to go backward in time when we then handle that event. Fix
that by invoking the whole event machine in this case, but
in order to simplify this, make reading the clock only cost
something when interrupts are not disabled. Otherwise, we'd
have to hook into the interrupt delivery machinery etc. and
that's somewhat intrusive.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This file isn't really shared, it's only used on the kernel side,
not on the user side. Remove the include from the user-side and
move the file to a better place.
While at it, rename it to time-internal.h, it's not really just
timers but all kinds of things related to timekeeping.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
When building UML with glibc 2.17 installed, compilation
of arch/um/os-Linux/file.c fails due to failure to find
FALLOC_FL_PUNCH_HOLE and FALLOC_FL_KEEP_SIZE definitions.
It appears that /usr/include/bits/fcntl-linux.h (indirectly
included by /usr/include/fcntl.h) does not include falloc.h
with an older glibc, whereas a more up-to-date version
does.
Adding the direct include to file.c resolves the issue
and does not cause problems for more recent glibc.
Fixes: 50109b5a03 ("um: Add support for DISCARD in the UBD Driver")
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Should bulk_req_safe_read return an error, we want to retry the read,
otherwise, even though no IO will be done, os_write_file might still end
up writing garbage to the pipe.
Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
