user/sven/linux.git/include/linux/sched.h, branch v4.4.20

pipe: limit the per-user amount of pages allocated in pipes

2016-06-08T01:14:35Z

commit 759c01142a5d0f364a462346168a56de28a80f52 upstream. On no-so-small systems, it is possible for a single process to cause an OOM condition by filling large pipes with data that are never read. A typical process filling 4000 pipes with 1 MB of data will use 4 GB of memory. On small systems it may be tricky to set the pipe max size to prevent this from happening. This patch makes it possible to enforce a per-user soft limit above which new pipes will be limited to a single page, effectively limiting them to 4 kB each, as well as a hard limit above which no new pipes may be created for this user. This has the effect of protecting the system against memory abuse without hurting other users, and still allowing pipes to work correctly though with less data at once. The limit are controlled by two new sysctls : pipe-user-pages-soft, and pipe-user-pages-hard. Both may be disabled by setting them to zero. The default soft limit allows the default number of FDs per process (1024) to create pipes of the default size (64kB), thus reaching a limit of 64MB before starting to create only smaller pipes. With 256 processes limited to 1024 FDs each, this results in 1024*64kB + (256*1024 - 1024) * 4kB = 1084 MB of memory allocated for a user. The hard limit is disabled by default to avoid breaking existing applications that make intensive use of pipes (eg: for splicing). Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds Signed-off-by: Willy Tarreau Signed-off-by: Al Viro Cc: Moritz Muehlenhoff Signed-off-by: Greg Kroah-Hartman

unix: properly account for FDs passed over unix sockets

2016-01-31T19:28:59Z

[ Upstream commit 712f4aad406bb1ed67f3f98d04c044191f0ff593 ] It is possible for a process to allocate and accumulate far more FDs than the process' limit by sending them over a unix socket then closing them to keep the process' fd count low. This change addresses this problem by keeping track of the number of FDs in flight per user and preventing non-privileged processes from having more FDs in flight than their configured FD limit. Reported-by: socketpair@gmail.com Reported-by: Tetsuo Handa Mitigates: CVE-2013-4312 (Linux 2.0+) Suggested-by: Linus Torvalds Acked-by: Hannes Frederic Sowa Signed-off-by: Willy Tarreau Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

sched/core: Fix unserialized r-m-w scribbling stuff

2016-01-06T10:01:07Z

Some of the sched bitfieds (notably sched_reset_on_fork) can be set on other than current, this can cause the r-m-w to race with other updates. Since all the sched bits are serialized by scheduler locks, pull them in a separate word. Reported-by: Tejun Heo Signed-off-by: Peter Zijlstra (Intel) Cc: Dmitry Vyukov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sasha Levin Cc: Thomas Gleixner Cc: akpm@linux-foundation.org Cc: hannes@cmpxchg.org Cc: mhocko@kernel.org Cc: vdavydov@parallels.com Link: http://lkml.kernel.org/r/20151125150207.GM11639@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar

sched/core: Check tgid in is_global_init()

2016-01-06T10:01:06Z

Our global init task can have sub-threads, so ->pid check is not reliable enough for is_global_init(), we need to check tgid instead. This has been spotted by Oleg and a fix was proposed by Richard a long time ago (see the link below). Oleg wrote: : Because is_global_init() is only true for the main thread of /sbin/init. : : Just look at oom_unkillable_task(). It tries to not kill init. But, say, : select_bad_process() can happily find a sub-thread of is_global_init() : and still kill it. I recently hit the problem in question; re-sending the patch (to the best of my knowledge it has never been submitted) with updated function comment. Credit goes to Oleg and Richard. Suggested-by: Richard Guy Briggs Reported-by: Oleg Nesterov Signed-off-by: Sergey Senozhatsky Signed-off-by: Peter Zijlstra (Intel) Acked-by: Serge Hallyn Cc: Andrew Morton Cc: Eric W . Biederman Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Serge E . Hallyn Cc: Sergey Senozhatsky Cc: Thomas Gleixner Link: https://www.redhat.com/archives/linux-audit/2013-December/msg00086.html Signed-off-by: Ingo Molnar

Merge tag 'libnvdimm-for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

2015-11-10T20:07:22Z

Pull libnvdimm updates from Dan Williams: "Outside of the new ACPI-NFIT hot-add support this pull request is more notable for what it does not contain, than what it does. There were a handful of development topics this cycle, dax get_user_pages, dax fsync, and raw block dax, that need more more iteration and will wait for 4.5. The patches to make devm and the pmem driver NUMA aware have been in -next for several weeks. The hot-add support has not, but is contained to the NFIT driver and is passing unit tests. The coredump support is straightforward and was looked over by Jeff. All of it has received a 0day build success notification across 107 configs. Summary: - Add support for the ACPI 6.0 NFIT hot add mechanism to process updates of the NFIT at runtime. - Teach the coredump implementation how to filter out DAX mappings. - Introduce NUMA hints for allocations made by the pmem driver, and as a side effect all devm allocations now hint their NUMA node by default" * tag 'libnvdimm-for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: coredump: add DAX filtering for FDPIC ELF coredumps coredump: add DAX filtering for ELF coredumps acpi: nfit: Add support for hot-add nfit: in acpi_nfit_init, break on a 0-length table pmem, memremap: convert to numa aware allocations devm_memremap_pages: use numa_mem_id devm: make allocations numa aware by default devm_memremap: convert to return ERR_PTR devm_memunmap: use devres_release() pmem: kill memremap_pmem() x86, mm: quiet arch_add_memory()

coredump: add DAX filtering for ELF coredumps

2015-11-09T18:29:54Z

Add two new flags to the existing coredump mechanism for ELF files to allow us to explicitly filter DAX mappings. This is desirable because DAX mappings, like hugetlb mappings, have the potential to be very large. Update the coredump_filter documentation in Documentation/filesystems/proc.txt so that it addresses the new DAX coredump flags. Also update the documented default value of coredump_filter to be consistent with the core(5) man page. The documentation being updated talks about bit 4, Dump ELF headers, which is enabled if CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is turned on in the kernel config. This kernel config option defaults to "y" if both ELF binaries and coredump are enabled. Signed-off-by: Ross Zwisler Acked-by: Jeff Moyer Signed-off-by: Dan Williams

signal: introduce kernel_signal_stop() to fix jffs2_garbage_collect_thread()

2015-11-07T01:50:42Z

jffs2_garbage_collect_thread() can race with SIGCONT and sleep in TASK_STOPPED state after it was already sent. Add the new helper, kernel_signal_stop(), which does this correctly. Signed-off-by: Oleg Nesterov Reviewed-by: Tejun Heo Cc: David Woodhouse Cc: Felipe Balbi Cc: Markus Pargmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signal: turn dequeue_signal_lock() into kernel_dequeue_signal()

2015-11-07T01:50:42Z

1. Rename dequeue_signal_lock() to kernel_dequeue_signal(). This matches another "for kthreads only" kernel_sigaction() helper. 2. Remove the "tsk" and "mask" arguments, they are always current and current->blocked. And it is simply wrong if tsk != current. 3. We could also remove the 3rd "siginfo_t *info" arg but it looks potentially useful. However we can simplify the callers if we change kernel_dequeue_signal() to accept info => NULL. 4. Remove _irqsave, it is never called from atomic context. Signed-off-by: Oleg Nesterov Reviewed-by: Tejun Heo Cc: David Woodhouse Cc: Felipe Balbi Cc: Markus Pargmann Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

signals: kill block_all_signals() and unblock_all_signals()

2015-11-07T01:50:42Z

It is hardly possible to enumerate all problems with block_all_signals() and unblock_all_signals(). Just for example, 1. block_all_signals(SIGSTOP/etc) simply can't help if the caller is multithreaded. Another thread can dequeue the signal and force the group stop. 2. Even is the caller is single-threaded, it will "stop" anyway. It will not sleep, but it will spin in kernel space until SIGCONT or SIGKILL. And a lot more. In short, this interface doesn't work at all, at least the last 10+ years. Daniel said: Yeah the only times I played around with the DRM_LOCK stuff was when old drivers accidentally deadlocked - my impression is that the entire DRM_LOCK thing was never really tested properly ;-) Hence I'm all for purging where this leaks out of the drm subsystem. Signed-off-by: Oleg Nesterov Acked-by: Daniel Vetter Acked-by: Dave Airlie Cc: Richard Weinberger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'akpm' (patches from Andrew)

2015-11-06T07:10:54Z

Merge patch-bomb from Andrew Morton: - inotify tweaks - some ocfs2 updates (many more are awaiting review) - various misc bits - kernel/watchdog.c updates - Some of mm. I have a huge number of MM patches this time and quite a lot of it is quite difficult and much will be held over to next time. * emailed patches from Andrew Morton : (162 commits) selftests: vm: add tests for lock on fault mm: mlock: add mlock flags to enable VM_LOCKONFAULT usage mm: introduce VM_LOCKONFAULT mm: mlock: add new mlock system call mm: mlock: refactor mlock, munlock, and munlockall code kasan: always taint kernel on report mm, slub, kasan: enable user tracking by default with KASAN=y kasan: use IS_ALIGNED in memory_is_poisoned_8() kasan: Fix a type conversion error lib: test_kasan: add some testcases kasan: update reference to kasan prototype repo kasan: move KASAN_SANITIZE in arch/x86/boot/Makefile kasan: various fixes in documentation kasan: update log messages kasan: accurately determine the type of the bad access kasan: update reported bug types for kernel memory accesses kasan: update reported bug types for not user nor kernel memory accesses mm/kasan: prevent deadlock in kasan reporting mm/kasan: don't use kasan shadow pointer in generic functions mm/kasan: MODULE_VADDR is not available on all archs ...