Currently, the exit_shm() function not designed to work properly when
task->sysvshm.shm_clist holds shm objects from different IPC namespaces.
This is a real pain when sysctl kernel.shm_rmid_forced = 1, because it
leads to use-after-free (reproducer exists).
This is an attempt to fix the problem by extending exit_shm mechanism to
handle shm's destroy from several IPC ns'es.
To achieve that we do several things:
1. add a namespace (non-refcounted) pointer to the struct shmid_kernel
2. during new shm object creation (newseg()/shmget syscall) we
initialize this pointer by current task IPC ns
3. exit_shm() fully reworked such that it traverses over all shp's in
task->sysvshm.shm_clist and gets IPC namespace not from current task
as it was before but from shp's object itself, then call
shm_destroy(shp, ns).
Note: We need to be really careful here, because as it was said before
(1), our pointer to IPC ns non-refcnt'ed. To be on the safe side we
using special helper get_ipc_ns_not_zero() which allows to get IPC ns
refcounter only if IPC ns not in the "state of destruction".
Q/A
Q: Why can we access shp->ns memory using non-refcounted pointer?
A: Because shp object lifetime is always shorther than IPC namespace
lifetime, so, if we get shp object from the task->sysvshm.shm_clist
while holding task_lock(task) nobody can steal our namespace.
Q: Does this patch change semantics of unshare/setns/clone syscalls?
A: No. It's just fixes non-covered case when process may leave IPC
namespace without getting task->sysvshm.shm_clist list cleaned up.
Link: https://lkml.kernel.org/r/67bb03e5-f79c-1815-e2bf-949c67047418@colorfullife.com
Link: https://lkml.kernel.org/r/20211109151501.4921-1-manfred@colorfullife.com
Fixes: ab602f79915 ("shm: make exit_shm work proportional to task activity")
Co-developed-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recently to prevent issues with SECCOMP_RET_KILL and similar signals
being changed before they are delivered SA_IMMUTABLE was added.
Unfortunately this broke debuggers[1][2] which reasonably expect
to be able to trap synchronous SIGTRAP and SIGSEGV even when
the target process is not configured to handle those signals.
Add force_exit_sig and use it instead of force_fatal_sig where
historically the code has directly called do_exit. This has the
implementation benefits of going through the signal exit path
(including generating core dumps) without the danger of allowing
userspace to ignore or change these signals.
This avoids userspace regressions as older kernels exited with do_exit
which debuggers also can not intercept.
In the future is should be possible to improve the quality of
implementation of the kernel by changing some of these force_exit_sig
calls to force_fatal_sig. That can be done where it matters on
a case-by-case basis with careful analysis.
Reported-by: Kyle Huey <me@kylehuey.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
[1] https://lkml.kernel.org/r/CAP045AoMY4xf8aC_4QU_-j7obuEPYgTcnQQP3Yxk=2X90jtpjw@mail.gmail.com
[2] https://lkml.kernel.org/r/20211117150258.GB5403@xsang-OptiPlex-9020
Fixes: 00b06da29cf9 ("signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed")
Fixes: a3616a3c0272 ("signal/m68k: Use force_sigsegv(SIGSEGV) in fpsp040_die")
Fixes: 83a1f27ad773 ("signal/powerpc: On swapcontext failure force SIGSEGV")
Fixes: 9bc508cf0791 ("signal/s390: Use force_sigsegv in default_trap_handler")
Fixes: 086ec444f866 ("signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig")
Fixes: c317d306d550 ("signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails")
Fixes: 695dd0d634df ("signal/x86: In emulate_vsyscall force a signal instead of calling do_exit")
Fixes: 1fbd60df8a85 ("signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved.")
Fixes: 941edc5bf174 ("exit/syscall_user_dispatch: Send ordinary signals on failure")
Link: https://lkml.kernel.org/r/871r3dqfv8.fsf_-_@email.froward.int.ebiederm.org
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Kyle Huey <khuey@kylehuey.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull exit cleanups from Eric Biederman: "While looking at some issues related to the exit path in the kernel I found several instances where the code is not using the existing abstractions properly. This set of changes introduces force_fatal_sig a way of sending a signal and not allowing it to be caught, and corrects the misuse of the existing abstractions that I found. A lot of the misuse of the existing abstractions are silly things such as doing something after calling a no return function, rolling BUG by hand, doing more work than necessary to terminate a kernel thread, or calling do_exit(SIGKILL) instead of calling force_sig(SIGKILL). In the review a deficiency in force_fatal_sig and force_sig_seccomp where ptrace or sigaction could prevent the delivery of the signal was found. I have added a change that adds SA_IMMUTABLE to change that makes it impossible to interrupt the delivery of those signals, and allows backporting to fix force_sig_seccomp And Arnd found an issue where a function passed to kthread_run had the wrong prototype, and after my cleanup was failing to build." * 'exit-cleanups-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (23 commits) soc: ti: fix wkup_m3_rproc_boot_thread return type signal: Add SA_IMMUTABLE to ensure forced siganls do not get changed signal: Replace force_sigsegv(SIGSEGV) with force_fatal_sig(SIGSEGV) exit/r8188eu: Replace the macro thread_exit with a simple return 0 exit/rtl8712: Replace the macro thread_exit with a simple return 0 exit/rtl8723bs: Replace the macro thread_exit with a simple return 0 signal/x86: In emulate_vsyscall force a signal instead of calling do_exit signal/sparc32: In setup_rt_frame and setup_fram use force_fatal_sig signal/sparc32: Exit with a fatal signal when try_to_clear_window_buffer fails exit/syscall_user_dispatch: Send ordinary signals on failure signal: Implement force_fatal_sig exit/kthread: Have kernel threads return instead of calling do_exit signal/s390: Use force_sigsegv in default_trap_handler signal/vm86_32: Properly send SIGSEGV when the vm86 state cannot be saved. signal/vm86_32: Replace open coded BUG_ON with an actual BUG_ON signal/sparc: In setup_tsb_params convert open coded BUG into BUG signal/powerpc: On swapcontext failure force SIGSEGV signal/sh: Use force_sig(SIGKILL) instead of do_group_exit(SIGKILL) signal/mips: Update (_save|_restore)_fp_context to fail with -EFAULT signal/sparc32: Remove unreachable do_exit in do_sparc_fault ...
Pull per signal_struct coredumps from Eric Biederman: "Current coredumps are mixed up with the exit code, the signal handling code, and the ptrace code making coredumps much more complicated than necessary and difficult to follow. This series of changes starts with ptrace_stop and cleans it up, making it easier to follow what is happening in ptrace_stop. Then cleans up the exec interactions with coredumps. Then cleans up the coredump interactions with exit. Finally the coredump interactions with the signal handling code is cleaned up. The first and last changes are bug fixes for minor bugs. I believe the fact that vfork followed by execve can kill the process the called vfork if exec fails is sufficient justification to change the userspace visible behavior. In previous discussions some of these changes were organized differently and individually appeared to make the code base worse. As currently written I believe they all stand on their own as cleanups and bug fixes. Which means that even if the worst should happen and the last change needs to be reverted for some unimaginable reason, the code base will still be improved. If the worst does not happen there are a more cleanups that can be made. Signals that generate coredumps can easily become eligible for short circuit delivery in complete_signal. The entire rendezvous for generating a coredump can move into get_signal. The function force_sig_info_to_task be written in a way that does not modify the signal handling state of the target task (because coredumps are eligible for short circuit delivery). Many of these future cleanups can be done another way but nothing so cleanly as if coredumps become per signal_struct" * 'per_signal_struct_coredumps-for-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: coredump: Limit coredumps to a single thread group coredump: Don't perform any cleanups before dumping core exit: Factor coredump_exit_mm out of exit_mm exec: Check for a pending fatal signal instead of core_state ptrace: Remove the unnecessary arguments from arch_ptrace_stop signal: Remove the bogus sigkill_pending in ptrace_stop
Pull parisc updates from Helge Deller:
"Lots of new features and fixes:
- Added TOC (table of content) support, which is a debugging feature
which is either initiated by pressing the TOC button or via command
in the BMC. If pressed the Linux built-in KDB/KGDB will be called
(Sven Schnelle)
- Fix CONFIG_PREEMPT (Sven)
- Fix unwinder on 64-bit kernels (Sven)
- Various kgdb fixes (Sven)
- Added KFENCE support (me)
- Switch to ARCH_STACKWALK implementation (me)
- Fix ptrace check on syscall return (me)
- Fix kernel crash with fixmaps on PA1.x machines (me)
- Move thread_info into task struct, aka CONFIG_THREAD_INFO_IN_TASK
(me)
- Updated defconfigs
- Smaller cleanups, including Makefile cleanups (Masahiro Yamada),
use kthread_run() macro (Cai Huoqing), use swap() macro (Yihao
Han)"
* tag 'for-5.16/parisc-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: (36 commits)
parisc: Fix set_fixmap() on PA1.x CPUs
parisc: Use swap() to swap values in setup_bootmem()
parisc: Update defconfigs
parisc: decompressor: clean up Makefile
parisc: decompressor: remove repeated depenency of misc.o
parisc: Remove unused constants from asm-offsets.c
parisc/ftrace: use static key to enable/disable function graph tracer
parisc/ftrace: set function trace function
parisc: Make use of the helper macro kthread_run()
parisc: mark xchg functions notrace
parisc: enhance warning regarding usage of O_NONBLOCK
parisc: Drop ifdef __KERNEL__ from non-uapi kernel headers
parisc: Use PRIV_USER and PRIV_KERNEL in ptrace.h
parisc: Use PRIV_USER in syscall.S
parisc/kgdb: add kgdb_roundup() to make kgdb work with idle polling
parisc: Move thread_info into task struct
parisc: add support for TOC (transfer of control)
parisc/firmware: add functions to retrieve TOC data
parisc: add PIM TOC data structures
parisc: move virt_map macro to assembly.h
...
Decay max_newidle_lb_cost only when it has not been updated for a while and ensure to not decay a recently changed value. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20211019123537.17146-4-vincent.guittot@linaro.org
The function end_of_stack() returns a pointer to the last entry of a stack. For architectures like parisc where the stack grows upwards return the pointer to the highest address in the stack. Without this change I faced a crash on parisc, because the stackleak functionality wrote STACKLEAK_POISON to the lowest address and thus overwrote the first 4 bytes of the task_struct which included the TIF_FLAGS. Signed-off-by: Helge Deller <deller@gmx.de>
Add a simple helper force_fatal_sig that causes a signal to be delivered to a process as if the signal handler was set to SIG_DFL. Reimplement force_sigsegv based upon this new helper. This fixes force_sigsegv so that when it forces the default signal handler to be used the code now forces the signal to be unblocked as well. Reusing the tested logic in force_sig_info_to_task that was built for force_sig_seccomp this makes the implementation trivial. This is interesting both because it makes force_sigsegv simpler and because there are a couple of buggy places in the kernel that call do_exit(SIGILL) or do_exit(SIGSYS) because there is no straight forward way today for those places to simply force the exit of a process with the chosen signal. Creating force_fatal_sig allows those places to be implemented with normal signal exits. Link: https://lkml.kernel.org/r/20211020174406.17889-13-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This patch adds scheduler level for clusters and automatically enables
the load balance among clusters. It will directly benefit a lot of
workload which loves more resources such as memory bandwidth, caches.
Testing has widely been done in two different hardware configurations of
Kunpeng920:
24 cores in one NUMA(6 clusters in each NUMA node);
32 cores in one NUMA(8 clusters in each NUMA node)
Workload is running on either one NUMA node or four NUMA nodes, thus,
this can estimate the effect of cluster spreading w/ and w/o NUMA load
balance.
* Stream benchmark:
4threads stream (on 1NUMA * 24cores = 24cores)
stream stream
w/o patch w/ patch
MB/sec copy 29929.64 ( 0.00%) 32932.68 ( 10.03%)
MB/sec scale 29861.10 ( 0.00%) 32710.58 ( 9.54%)
MB/sec add 27034.42 ( 0.00%) 32400.68 ( 19.85%)
MB/sec triad 27225.26 ( 0.00%) 31965.36 ( 17.41%)
6threads stream (on 1NUMA * 24cores = 24cores)
stream stream
w/o patch w/ patch
MB/sec copy 40330.24 ( 0.00%) 42377.68 ( 5.08%)
MB/sec scale 40196.42 ( 0.00%) 42197.90 ( 4.98%)
MB/sec add 37427.00 ( 0.00%) 41960.78 ( 12.11%)
MB/sec triad 37841.36 ( 0.00%) 42513.64 ( 12.35%)
12threads stream (on 1NUMA * 24cores = 24cores)
stream stream
w/o patch w/ patch
MB/sec copy 52639.82 ( 0.00%) 53818.04 ( 2.24%)
MB/sec scale 52350.30 ( 0.00%) 53253.38 ( 1.73%)
MB/sec add 53607.68 ( 0.00%) 55198.82 ( 2.97%)
MB/sec triad 54776.66 ( 0.00%) 56360.40 ( 2.89%)
Thus, it could help memory-bound workload especially under medium load.
Similar improvement is also seen in lkp-pbzip2:
* lkp-pbzip2 benchmark
2-96 threads (on 4NUMA * 24cores = 96cores)
lkp-pbzip2 lkp-pbzip2
w/o patch w/ patch
Hmean tput-2 11062841.57 ( 0.00%) 11341817.51 * 2.52%*
Hmean tput-5 26815503.70 ( 0.00%) 27412872.65 * 2.23%*
Hmean tput-8 41873782.21 ( 0.00%) 43326212.92 * 3.47%*
Hmean tput-12 61875980.48 ( 0.00%) 64578337.51 * 4.37%*
Hmean tput-21 105814963.07 ( 0.00%) 111381851.01 * 5.26%*
Hmean tput-30 150349470.98 ( 0.00%) 156507070.73 * 4.10%*
Hmean tput-48 237195937.69 ( 0.00%) 242353597.17 * 2.17%*
Hmean tput-79 360252509.37 ( 0.00%) 362635169.23 * 0.66%*
Hmean tput-96 394571737.90 ( 0.00%) 400952978.48 * 1.62%*
2-24 threads (on 1NUMA * 24cores = 24cores)
lkp-pbzip2 lkp-pbzip2
w/o patch w/ patch
Hmean tput-2 11071705.49 ( 0.00%) 11296869.10 * 2.03%*
Hmean tput-4 20782165.19 ( 0.00%) 21949232.15 * 5.62%*
Hmean tput-6 30489565.14 ( 0.00%) 33023026.96 * 8.31%*
Hmean tput-8 40376495.80 ( 0.00%) 42779286.27 * 5.95%*
Hmean tput-12 61264033.85 ( 0.00%) 62995632.78 * 2.83%*
Hmean tput-18 86697139.39 ( 0.00%) 86461545.74 ( -0.27%)
Hmean tput-24 104854637.04 ( 0.00%) 104522649.46 * -0.32%*
In the case of 6 threads and 8 threads, we see the greatest performance
improvement.
Similar improvement can be seen on lkp-pixz though the improvement is
smaller:
* lkp-pixz benchmark
2-24 threads lkp-pixz (on 1NUMA * 24cores = 24cores)
lkp-pixz lkp-pixz
w/o patch w/ patch
Hmean tput-2 6486981.16 ( 0.00%) 6561515.98 * 1.15%*
Hmean tput-4 11645766.38 ( 0.00%) 11614628.43 ( -0.27%)
Hmean tput-6 15429943.96 ( 0.00%) 15957350.76 * 3.42%*
Hmean tput-8 19974087.63 ( 0.00%) 20413746.98 * 2.20%*
Hmean tput-12 28172068.18 ( 0.00%) 28751997.06 * 2.06%*
Hmean tput-18 39413409.54 ( 0.00%) 39896830.55 * 1.23%*
Hmean tput-24 49101815.85 ( 0.00%) 49418141.47 * 0.64%*
* SPECrate benchmark
4,8,16 copies mcf_r(on 1NUMA * 32cores = 32cores)
Base Base
Run Time Rate
------- ---------
4 Copies w/o 580 (w/ 570) w/o 11.1 (w/ 11.3)
8 Copies w/o 647 (w/ 605) w/o 20.0 (w/ 21.4, +7%)
16 Copies w/o 844 (w/ 844) w/o 30.6 (w/ 30.6)
32 Copies(on 4NUMA * 32 cores = 128cores)
[w/o patch]
Base Base Base
Benchmarks Copies Run Time Rate
--------------- ------- --------- ---------
500.perlbench_r 32 584 87.2 *
502.gcc_r 32 503 90.2 *
505.mcf_r 32 745 69.4 *
520.omnetpp_r 32 1031 40.7 *
523.xalancbmk_r 32 597 56.6 *
525.x264_r 1 -- CE
531.deepsjeng_r 32 336 109 *
541.leela_r 32 556 95.4 *
548.exchange2_r 32 513 163 *
557.xz_r 32 530 65.2 *
Est. SPECrate2017_int_base 80.3
[w/ patch]
Base Base Base
Benchmarks Copies Run Time Rate
--------------- ------- --------- ---------
500.perlbench_r 32 580 87.8 (+0.688%) *
502.gcc_r 32 477 95.1 (+5.432%) *
505.mcf_r 32 644 80.3 (+13.574%) *
520.omnetpp_r 32 942 44.6 (+9.58%) *
523.xalancbmk_r 32 560 60.4 (+6.714%%) *
525.x264_r 1 -- CE
531.deepsjeng_r 32 337 109 (+0.000%) *
541.leela_r 32 554 95.6 (+0.210%) *
548.exchange2_r 32 515 163 (+0.000%) *
557.xz_r 32 524 66.0 (+1.227%) *
Est. SPECrate2017_int_base 83.7 (+4.062%)
On the other hand, it is slightly helpful to CPU-bound tasks like
kernbench:
* 24-96 threads kernbench (on 4NUMA * 24cores = 96cores)
kernbench kernbench
w/o cluster w/ cluster
Min user-24 12054.67 ( 0.00%) 12024.19 ( 0.25%)
Min syst-24 1751.51 ( 0.00%) 1731.68 ( 1.13%)
Min elsp-24 600.46 ( 0.00%) 598.64 ( 0.30%)
Min user-48 12361.93 ( 0.00%) 12315.32 ( 0.38%)
Min syst-48 1917.66 ( 0.00%) 1892.73 ( 1.30%)
Min elsp-48 333.96 ( 0.00%) 332.57 ( 0.42%)
Min user-96 12922.40 ( 0.00%) 12921.17 ( 0.01%)
Min syst-96 2143.94 ( 0.00%) 2110.39 ( 1.56%)
Min elsp-96 211.22 ( 0.00%) 210.47 ( 0.36%)
Amean user-24 12063.99 ( 0.00%) 12030.78 * 0.28%*
Amean syst-24 1755.20 ( 0.00%) 1735.53 * 1.12%*
Amean elsp-24 601.60 ( 0.00%) 600.19 ( 0.23%)
Amean user-48 12362.62 ( 0.00%) 12315.56 * 0.38%*
Amean syst-48 1921.59 ( 0.00%) 1894.95 * 1.39%*
Amean elsp-48 334.10 ( 0.00%) 332.82 * 0.38%*
Amean user-96 12925.27 ( 0.00%) 12922.63 ( 0.02%)
Amean syst-96 2146.66 ( 0.00%) 2122.20 * 1.14%*
Amean elsp-96 211.96 ( 0.00%) 211.79 ( 0.08%)
Note this patch isn't an universal win, it might hurt those workload
which can benefit from packing. Though tasks which want to take
advantages of lower communication latency of one cluster won't
necessarily been packed in one cluster while kernel is not aware of
clusters, they have some chance to be randomly packed. But this
patch will make them more likely spread.
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
There is a small race between copy_process() and sched_fork()
where child->sched_task_group point to an already freed pointer.
parent doing fork() | someone moving the parent
| to another cgroup
-------------------------------+-------------------------------
copy_process()
+ dup_task_struct()<1>
parent move to another cgroup,
and free the old cgroup. <2>
+ sched_fork()
+ __set_task_cpu()<3>
+ task_fork_fair()
+ sched_slice()<4>
In the worst case, this bug can lead to "use-after-free" and
cause panic as shown above:
(1) parent copy its sched_task_group to child at <1>;
(2) someone move the parent to another cgroup and free the old
cgroup at <2>;
(3) the sched_task_group and cfs_rq that belong to the old cgroup
will be accessed at <3> and <4>, which cause a panic:
[] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[] PGD 8000001fa0a86067 P4D 8000001fa0a86067 PUD 2029955067 PMD 0
[] Oops: 0000 [#1] SMP PTI
[] CPU: 7 PID: 648398 Comm: ebizzy Kdump: loaded Tainted: G OE --------- - - 4.18.0.x86_64+ #1
[] RIP: 0010:sched_slice+0x84/0xc0
[] Call Trace:
[] task_fork_fair+0x81/0x120
[] sched_fork+0x132/0x240
[] copy_process.part.5+0x675/0x20e0
[] ? __handle_mm_fault+0x63f/0x690
[] _do_fork+0xcd/0x3b0
[] do_syscall_64+0x5d/0x1d0
[] entry_SYSCALL_64_after_hwframe+0x65/0xca
[] RIP: 0033:0x7f04418cd7e1
Between cgroup_can_fork() and cgroup_post_fork(), the cgroup
membership and thus sched_task_group can't change. So update child's
sched_task_group at sched_post_fork() and move task_fork() and
__set_task_cpu() (where accees the sched_task_group) from sched_fork()
to sched_post_fork().
Fixes: 8323f26ce342 ("sched: Fix race in task_group")
Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lkml.kernel.org/r/20210915064030.2231-1-zhangqiao22@huawei.com