linux-stable/init/init_task.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
// SPDX-License-Identifier: GPL-2.0
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#include <linux/init_task.h>
#include <linux/export.h>
#include <linux/mqueue.h>
#include <linux/sched.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/rt.h>
#include <linux/sched/task.h>
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#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/audit.h>
mm: replace all open encodings for NUMA_NO_NODE Patch series "Replace all open encodings for NUMA_NO_NODE", v3. All these places for replacement were found by running the following grep patterns on the entire kernel code. Please let me know if this might have missed some instances. This might also have replaced some false positives. I will appreciate suggestions, inputs and review. 1. git grep "nid == -1" 2. git grep "node == -1" 3. git grep "nid = -1" 4. git grep "node = -1" This patch (of 2): At present there are multiple places where invalid node number is encoded as -1. Even though implicitly understood it is always better to have macros in there. Replace these open encodings for an invalid node number with the global macro NUMA_NO_NODE. This helps remove NUMA related assumptions like 'invalid node' from various places redirecting them to a common definition. Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [ixgbe] Acked-by: Jens Axboe <axboe@kernel.dk> [mtip32xx] Acked-by: Vinod Koul <vkoul@kernel.org> [dmaengine.c] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Doug Ledford <dledford@redhat.com> [drivers/infiniband] Cc: Joseph Qi <jiangqi903@gmail.com> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 23:42:58 +00:00
#include <linux/numa.h>
#include <linux/scs.h>
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#include <linux/uaccess.h>
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static struct signal_struct init_signals = {
.nr_threads = 1,
.thread_head = LIST_HEAD_INIT(init_task.thread_node),
.wait_chldexit = __WAIT_QUEUE_HEAD_INITIALIZER(init_signals.wait_chldexit),
.shared_pending = {
.list = LIST_HEAD_INIT(init_signals.shared_pending.list),
.signal = {{0}}
},
signal: Don't restart fork when signals come in. Wen Yang <wen.yang99@zte.com.cn> and majiang <ma.jiang@zte.com.cn> report that a periodic signal received during fork can cause fork to continually restart preventing an application from making progress. The code was being overly pessimistic. Fork needs to guarantee that a signal sent to multiple processes is logically delivered before the fork and just to the forking process or logically delivered after the fork to both the forking process and it's newly spawned child. For signals like periodic timers that are always delivered to a single process fork can safely complete and let them appear to logically delivered after the fork(). While examining this issue I also discovered that fork today will miss signals delivered to multiple processes during the fork and handled by another thread. Similarly the current code will also miss blocked signals that are delivered to multiple process, as those signals will not appear pending during fork. Add a list of each thread that is currently forking, and keep on that list a signal set that records all of the signals sent to multiple processes. When fork completes initialize the new processes shared_pending signal set with it. The calculate_sigpending function will see those signals and set TIF_SIGPENDING causing the new task to take the slow path to userspace to handle those signals. Making it appear as if those signals were received immediately after the fork. It is not possible to send real time signals to multiple processes and exceptions don't go to multiple processes, which means that that are no signals sent to multiple processes that require siginfo. This means it is safe to not bother collecting siginfo on signals sent during fork. The sigaction of a child of fork is initially the same as the sigaction of the parent process. So a signal the parent ignores the child will also initially ignore. Therefore it is safe to ignore signals sent to multiple processes and ignored by the forking process. Signals sent to only a single process or only a single thread and delivered during fork are treated as if they are received after the fork, and generally not dealt with. They won't cause any problems. V2: Added removal from the multiprocess list on failure. V3: Use -ERESTARTNOINTR directly V4: - Don't queue both SIGCONT and SIGSTOP - Initialize signal_struct.multiprocess in init_task - Move setting of shared_pending to before the new task is visible to signals. This prevents signals from comming in before shared_pending.signal is set to delayed.signal and being lost. V5: - rework list add and delete to account for idle threads v6: - Use sigdelsetmask when removing stop signals Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=200447 Reported-by: Wen Yang <wen.yang99@zte.com.cn> and Reported-by: majiang <ma.jiang@zte.com.cn> Fixes: 4a2c7a7837da ("[PATCH] make fork() atomic wrt pgrp/session signals") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2018-07-23 20:20:37 +00:00
.multiprocess = HLIST_HEAD_INIT,
.rlim = INIT_RLIMITS,
.cred_guard_mutex = __MUTEX_INITIALIZER(init_signals.cred_guard_mutex),
exec: Transform exec_update_mutex into a rw_semaphore Recently syzbot reported[0] that there is a deadlock amongst the users of exec_update_mutex. The problematic lock ordering found by lockdep was: perf_event_open (exec_update_mutex -> ovl_i_mutex) chown (ovl_i_mutex -> sb_writes) sendfile (sb_writes -> p->lock) by reading from a proc file and writing to overlayfs proc_pid_syscall (p->lock -> exec_update_mutex) While looking at possible solutions it occured to me that all of the users and possible users involved only wanted to state of the given process to remain the same. They are all readers. The only writer is exec. There is no reason for readers to block on each other. So fix this deadlock by transforming exec_update_mutex into a rw_semaphore named exec_update_lock that only exec takes for writing. Cc: Jann Horn <jannh@google.com> Cc: Vasiliy Kulikov <segoon@openwall.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Bernd Edlinger <bernd.edlinger@hotmail.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Christopher Yeoh <cyeoh@au1.ibm.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Sargun Dhillon <sargun@sargun.me> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Fixes: eea9673250db ("exec: Add exec_update_mutex to replace cred_guard_mutex") [0] https://lkml.kernel.org/r/00000000000063640c05ade8e3de@google.com Reported-by: syzbot+db9cdf3dd1f64252c6ef@syzkaller.appspotmail.com Link: https://lkml.kernel.org/r/87ft4mbqen.fsf@x220.int.ebiederm.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2020-12-03 20:12:00 +00:00
.exec_update_lock = __RWSEM_INITIALIZER(init_signals.exec_update_lock),
#ifdef CONFIG_POSIX_TIMERS
.posix_timers = LIST_HEAD_INIT(init_signals.posix_timers),
.cputimer = {
.cputime_atomic = INIT_CPUTIME_ATOMIC,
},
#endif
INIT_CPU_TIMERS(init_signals)
.pids = {
[PIDTYPE_PID] = &init_struct_pid,
[PIDTYPE_TGID] = &init_struct_pid,
[PIDTYPE_PGID] = &init_struct_pid,
[PIDTYPE_SID] = &init_struct_pid,
},
INIT_PREV_CPUTIME(init_signals)
};
static struct sighand_struct init_sighand = {
sched/core: Convert signal_struct.sigcnt to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable signal_struct.sigcnt is used as pure reference counter. Convert it to refcount_t and fix up the operations. ** Important note for maintainers: Some functions from refcount_t API defined in lib/refcount.c have different memory ordering guarantees than their atomic counterparts. The full comparison can be seen in https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon in state to be merged to the documentation tree. Normally the differences should not matter since refcount_t provides enough guarantees to satisfy the refcounting use cases, but in some rare cases it might matter. Please double check that you don't have some undocumented memory guarantees for this variable usage. For the signal_struct.sigcnt it might make a difference in following places: - put_signal_struct(): decrement in refcount_dec_and_test() only provides RELEASE ordering and control dependency on success vs. fully ordered atomic counterpart Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: viro@zeniv.linux.org.uk Link: https://lkml.kernel.org/r/1547814450-18902-3-git-send-email-elena.reshetova@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-18 12:27:27 +00:00
.count = REFCOUNT_INIT(1),
.action = { { { .sa_handler = SIG_DFL, } }, },
.siglock = __SPIN_LOCK_UNLOCKED(init_sighand.siglock),
.signalfd_wqh = __WAIT_QUEUE_HEAD_INITIALIZER(init_sighand.signalfd_wqh),
};
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#ifdef CONFIG_SHADOW_CALL_STACK
unsigned long init_shadow_call_stack[SCS_SIZE / sizeof(long)]
__init_task_data = {
[(SCS_SIZE / sizeof(long)) - 1] = SCS_END_MAGIC
};
#endif
/*
* Set up the first task table, touch at your own risk!. Base=0,
* limit=0x1fffff (=2MB)
*/
struct task_struct init_task
#ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
__init_task_data
#endif
init: Align init_task to avoid conflict with MUTEX_FLAGS When booting on 32-bit machines (seen on OpenRISC) I saw this warning with CONFIG_DEBUG_MUTEXES turned on. ------------[ cut here ]------------ WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:1242 __mutex_unlock_slowpath+0x328/0x3ec DEBUG_LOCKS_WARN_ON(__owner_task(owner) != current) Modules linked in: CPU: 0 PID: 0 Comm: swapper Not tainted 5.8.0-rc1-simple-smp-00005-g2864e2171db4-dirty #179 Call trace: [<(ptrval)>] dump_stack+0x34/0x48 [<(ptrval)>] __warn+0x104/0x158 [<(ptrval)>] ? __mutex_unlock_slowpath+0x328/0x3ec [<(ptrval)>] warn_slowpath_fmt+0x7c/0x94 [<(ptrval)>] __mutex_unlock_slowpath+0x328/0x3ec [<(ptrval)>] mutex_unlock+0x18/0x28 [<(ptrval)>] __cpuhp_setup_state_cpuslocked.part.0+0x29c/0x2f4 [<(ptrval)>] ? page_alloc_cpu_dead+0x0/0x30 [<(ptrval)>] ? start_kernel+0x0/0x684 [<(ptrval)>] __cpuhp_setup_state+0x4c/0x5c [<(ptrval)>] page_alloc_init+0x34/0x68 [<(ptrval)>] ? start_kernel+0x1a0/0x684 [<(ptrval)>] ? early_init_dt_scan_nodes+0x60/0x70 irq event stamp: 0 I traced this to kernel/locking/mutex.c storing 3 bits of MUTEX_FLAGS in the task_struct pointer (mutex.owner). There is a comment saying that task_structs are always aligned to L1_CACHE_BYTES. This is not true for the init_task. On 64-bit machines this is not a problem because symbol addresses are naturally aligned to 64-bits providing 3 bits for MUTEX_FLAGS. Howerver, for 32-bit machines the symbol address only has 2 bits available. Fix this by setting init_task alignment to at least L1_CACHE_BYTES. Signed-off-by: Stafford Horne <shorne@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-06-25 20:24:24 +00:00
__aligned(L1_CACHE_BYTES)
= {
#ifdef CONFIG_THREAD_INFO_IN_TASK
.thread_info = INIT_THREAD_INFO(init_task),
sched/core: Convert task_struct.stack_refcount to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable task_struct.stack_refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. ** Important note for maintainers: Some functions from refcount_t API defined in lib/refcount.c have different memory ordering guarantees than their atomic counterparts. The full comparison can be seen in https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon in state to be merged to the documentation tree. Normally the differences should not matter since refcount_t provides enough guarantees to satisfy the refcounting use cases, but in some rare cases it might matter. Please double check that you don't have some undocumented memory guarantees for this variable usage. For the task_struct.stack_refcount it might make a difference in following places: - try_get_task_stack(): increment in refcount_inc_not_zero() only guarantees control dependency on success vs. fully ordered atomic counterpart - put_task_stack(): decrement in refcount_dec_and_test() only provides RELEASE ordering and control dependency on success vs. fully ordered atomic counterpart Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: viro@zeniv.linux.org.uk Link: https://lkml.kernel.org/r/1547814450-18902-6-git-send-email-elena.reshetova@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-18 12:27:30 +00:00
.stack_refcount = REFCOUNT_INIT(1),
#endif
.state = 0,
.stack = init_stack,
sched/core: Convert task_struct.usage to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable task_struct.usage is used as pure reference counter. Convert it to refcount_t and fix up the operations. ** Important note for maintainers: Some functions from refcount_t API defined in lib/refcount.c have different memory ordering guarantees than their atomic counterparts. The full comparison can be seen in https://lkml.org/lkml/2017/11/15/57 and it is hopefully soon in state to be merged to the documentation tree. Normally the differences should not matter since refcount_t provides enough guarantees to satisfy the refcounting use cases, but in some rare cases it might matter. Please double check that you don't have some undocumented memory guarantees for this variable usage. For the task_struct.usage it might make a difference in following places: - put_task_struct(): decrement in refcount_dec_and_test() only provides RELEASE ordering and control dependency on success vs. fully ordered atomic counterpart Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: David Windsor <dwindsor@gmail.com> Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com> Reviewed-by: Andrea Parri <andrea.parri@amarulasolutions.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: viro@zeniv.linux.org.uk Link: https://lkml.kernel.org/r/1547814450-18902-5-git-send-email-elena.reshetova@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-18 12:27:29 +00:00
.usage = REFCOUNT_INIT(2),
.flags = PF_KTHREAD,
.prio = MAX_PRIO - 20,
.static_prio = MAX_PRIO - 20,
.normal_prio = MAX_PRIO - 20,
.policy = SCHED_NORMAL,
.cpus_ptr = &init_task.cpus_mask,
.cpus_mask = CPU_MASK_ALL,
.nr_cpus_allowed= NR_CPUS,
.mm = NULL,
.active_mm = &init_mm,
.restart_block = {
.fn = do_no_restart_syscall,
},
.se = {
.group_node = LIST_HEAD_INIT(init_task.se.group_node),
},
.rt = {
.run_list = LIST_HEAD_INIT(init_task.rt.run_list),
.time_slice = RR_TIMESLICE,
},
.tasks = LIST_HEAD_INIT(init_task.tasks),
#ifdef CONFIG_SMP
.pushable_tasks = PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
#endif
#ifdef CONFIG_CGROUP_SCHED
.sched_task_group = &root_task_group,
#endif
.ptraced = LIST_HEAD_INIT(init_task.ptraced),
.ptrace_entry = LIST_HEAD_INIT(init_task.ptrace_entry),
.real_parent = &init_task,
.parent = &init_task,
.children = LIST_HEAD_INIT(init_task.children),
.sibling = LIST_HEAD_INIT(init_task.sibling),
.group_leader = &init_task,
RCU_POINTER_INITIALIZER(real_cred, &init_cred),
RCU_POINTER_INITIALIZER(cred, &init_cred),
.comm = INIT_TASK_COMM,
.thread = INIT_THREAD,
.fs = &init_fs,
.files = &init_files,
#ifdef CONFIG_IO_URING
.io_uring = NULL,
#endif
.signal = &init_signals,
.sighand = &init_sighand,
.nsproxy = &init_nsproxy,
.pending = {
.list = LIST_HEAD_INIT(init_task.pending.list),
.signal = {{0}}
},
.blocked = {{0}},
.alloc_lock = __SPIN_LOCK_UNLOCKED(init_task.alloc_lock),
.journal_info = NULL,
INIT_CPU_TIMERS(init_task)
.pi_lock = __RAW_SPIN_LOCK_UNLOCKED(init_task.pi_lock),
.timer_slack_ns = 50000, /* 50 usec default slack */
.thread_pid = &init_struct_pid,
.thread_group = LIST_HEAD_INIT(init_task.thread_group),
.thread_node = LIST_HEAD_INIT(init_signals.thread_head),
#ifdef CONFIG_AUDIT
.loginuid = INVALID_UID,
.sessionid = AUDIT_SID_UNSET,
#endif
#ifdef CONFIG_PERF_EVENTS
.perf_event_mutex = __MUTEX_INITIALIZER(init_task.perf_event_mutex),
.perf_event_list = LIST_HEAD_INIT(init_task.perf_event_list),
#endif
#ifdef CONFIG_PREEMPT_RCU
.rcu_read_lock_nesting = 0,
.rcu_read_unlock_special.s = 0,
.rcu_node_entry = LIST_HEAD_INIT(init_task.rcu_node_entry),
.rcu_blocked_node = NULL,
#endif
#ifdef CONFIG_TASKS_RCU
.rcu_tasks_holdout = false,
.rcu_tasks_holdout_list = LIST_HEAD_INIT(init_task.rcu_tasks_holdout_list),
.rcu_tasks_idle_cpu = -1,
#endif
rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks Because RCU does not watch exception early-entry/late-exit, idle-loop, or CPU-hotplug execution, protection of tracing and BPF operations is needlessly complicated. This commit therefore adds a variant of Tasks RCU that: o Has explicit read-side markers to allow finite grace periods in the face of in-kernel loops for PREEMPT=n builds. These markers are rcu_read_lock_trace() and rcu_read_unlock_trace(). o Protects code in the idle loop, exception entry/exit, and CPU-hotplug code paths. In this respect, RCU-tasks trace is similar to SRCU, but with lighter-weight readers. o Avoids expensive read-side instruction, having overhead similar to that of Preemptible RCU. There are of course downsides: o The grace-period code can send IPIs to CPUs, even when those CPUs are in the idle loop or in nohz_full userspace. This is mitigated by later commits. o It is necessary to scan the full tasklist, much as for Tasks RCU. o There is a single callback queue guarded by a single lock, again, much as for Tasks RCU. However, those early use cases that request multiple grace periods in quick succession are expected to do so from a single task, which makes the single lock almost irrelevant. If needed, multiple callback queues can be provided using any number of schemes. Perhaps most important, this variant of RCU does not affect the vanilla flavors, rcu_preempt and rcu_sched. The fact that RCU Tasks Trace readers can operate from idle, offline, and exception entry/exit in no way enables rcu_preempt and rcu_sched readers to do so. The memory ordering was outlined here: https://lore.kernel.org/lkml/20200319034030.GX3199@paulmck-ThinkPad-P72/ This effort benefited greatly from off-list discussions of BPF requirements with Alexei Starovoitov and Andrii Nakryiko. At least some of the on-list discussions are captured in the Link: tags below. In addition, KCSAN was quite helpful in finding some early bugs. Link: https://lore.kernel.org/lkml/20200219150744.428764577@infradead.org/ Link: https://lore.kernel.org/lkml/87mu8p797b.fsf@nanos.tec.linutronix.de/ Link: https://lore.kernel.org/lkml/20200225221305.605144982@linutronix.de/ Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andriin@fb.com> [ paulmck: Apply feedback from Steve Rostedt and Joel Fernandes. ] [ paulmck: Decrement trc_n_readers_need_end upon IPI failure. ] [ paulmck: Fix locking issue reported by rcutorture. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-03-10 02:56:53 +00:00
#ifdef CONFIG_TASKS_TRACE_RCU
.trc_reader_nesting = 0,
.trc_reader_special.s = 0,
rcu-tasks: Add an RCU Tasks Trace to simplify protection of tracing hooks Because RCU does not watch exception early-entry/late-exit, idle-loop, or CPU-hotplug execution, protection of tracing and BPF operations is needlessly complicated. This commit therefore adds a variant of Tasks RCU that: o Has explicit read-side markers to allow finite grace periods in the face of in-kernel loops for PREEMPT=n builds. These markers are rcu_read_lock_trace() and rcu_read_unlock_trace(). o Protects code in the idle loop, exception entry/exit, and CPU-hotplug code paths. In this respect, RCU-tasks trace is similar to SRCU, but with lighter-weight readers. o Avoids expensive read-side instruction, having overhead similar to that of Preemptible RCU. There are of course downsides: o The grace-period code can send IPIs to CPUs, even when those CPUs are in the idle loop or in nohz_full userspace. This is mitigated by later commits. o It is necessary to scan the full tasklist, much as for Tasks RCU. o There is a single callback queue guarded by a single lock, again, much as for Tasks RCU. However, those early use cases that request multiple grace periods in quick succession are expected to do so from a single task, which makes the single lock almost irrelevant. If needed, multiple callback queues can be provided using any number of schemes. Perhaps most important, this variant of RCU does not affect the vanilla flavors, rcu_preempt and rcu_sched. The fact that RCU Tasks Trace readers can operate from idle, offline, and exception entry/exit in no way enables rcu_preempt and rcu_sched readers to do so. The memory ordering was outlined here: https://lore.kernel.org/lkml/20200319034030.GX3199@paulmck-ThinkPad-P72/ This effort benefited greatly from off-list discussions of BPF requirements with Alexei Starovoitov and Andrii Nakryiko. At least some of the on-list discussions are captured in the Link: tags below. In addition, KCSAN was quite helpful in finding some early bugs. Link: https://lore.kernel.org/lkml/20200219150744.428764577@infradead.org/ Link: https://lore.kernel.org/lkml/87mu8p797b.fsf@nanos.tec.linutronix.de/ Link: https://lore.kernel.org/lkml/20200225221305.605144982@linutronix.de/ Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andriin@fb.com> [ paulmck: Apply feedback from Steve Rostedt and Joel Fernandes. ] [ paulmck: Decrement trc_n_readers_need_end upon IPI failure. ] [ paulmck: Fix locking issue reported by rcutorture. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-03-10 02:56:53 +00:00
.trc_holdout_list = LIST_HEAD_INIT(init_task.trc_holdout_list),
#endif
#ifdef CONFIG_CPUSETS
.mems_allowed_seq = SEQCNT_SPINLOCK_ZERO(init_task.mems_allowed_seq,
&init_task.alloc_lock),
#endif
#ifdef CONFIG_RT_MUTEXES
.pi_waiters = RB_ROOT_CACHED,
.pi_top_task = NULL,
#endif
INIT_PREV_CPUTIME(init_task)
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
.vtime.seqcount = SEQCNT_ZERO(init_task.vtime_seqcount),
.vtime.starttime = 0,
.vtime.state = VTIME_SYS,
#endif
#ifdef CONFIG_NUMA_BALANCING
mm: replace all open encodings for NUMA_NO_NODE Patch series "Replace all open encodings for NUMA_NO_NODE", v3. All these places for replacement were found by running the following grep patterns on the entire kernel code. Please let me know if this might have missed some instances. This might also have replaced some false positives. I will appreciate suggestions, inputs and review. 1. git grep "nid == -1" 2. git grep "node == -1" 3. git grep "nid = -1" 4. git grep "node = -1" This patch (of 2): At present there are multiple places where invalid node number is encoded as -1. Even though implicitly understood it is always better to have macros in there. Replace these open encodings for an invalid node number with the global macro NUMA_NO_NODE. This helps remove NUMA related assumptions like 'invalid node' from various places redirecting them to a common definition. Link: http://lkml.kernel.org/r/1545127933-10711-2-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: David Hildenbrand <david@redhat.com> Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com> [ixgbe] Acked-by: Jens Axboe <axboe@kernel.dk> [mtip32xx] Acked-by: Vinod Koul <vkoul@kernel.org> [dmaengine.c] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Doug Ledford <dledford@redhat.com> [drivers/infiniband] Cc: Joseph Qi <jiangqi903@gmail.com> Cc: Hans Verkuil <hverkuil@xs4all.nl> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-03-05 23:42:58 +00:00
.numa_preferred_nid = NUMA_NO_NODE,
.numa_group = NULL,
.numa_faults = NULL,
#endif
#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
.kasan_depth = 1,
#endif
#ifdef CONFIG_KCSAN
.kcsan_ctx = {
.disable_count = 0,
.atomic_next = 0,
.atomic_nest_count = 0,
.in_flat_atomic = false,
.access_mask = 0,
kcsan: Add support for scoped accesses This adds support for scoped accesses, where the memory range is checked for the duration of the scope. The feature is implemented by inserting the relevant access information into a list of scoped accesses for the current execution context, which are then checked (until removed) on every call (through instrumentation) into the KCSAN runtime. An alternative, more complex, implementation could set up a watchpoint for the scoped access, and keep the watchpoint set up. This, however, would require first exposing a handle to the watchpoint, as well as dealing with cases such as accesses by the same thread while the watchpoint is still set up (and several more cases). It is also doubtful if this would provide any benefit, since the majority of delay where the watchpoint is set up is likely due to the injected delays by KCSAN. Therefore, the implementation in this patch is simpler and avoids hurting KCSAN's main use-case (normal data race detection); it also implicitly increases scoped-access race-detection-ability due to increased probability of setting up watchpoints by repeatedly calling __kcsan_check_access() throughout the scope of the access. The implementation required adding an additional conditional branch to the fast-path. However, the microbenchmark showed a *speedup* of ~5% on the fast-path. This appears to be due to subtly improved codegen by GCC from moving get_ctx() and associated load of preempt_count earlier. Suggested-by: Boqun Feng <boqun.feng@gmail.com> Suggested-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-03-25 16:41:56 +00:00
.scoped_accesses = {LIST_POISON1, NULL},
},
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
.softirqs_enabled = 1,
#endif
#ifdef CONFIG_LOCKDEP
.lockdep_depth = 0, /* no locks held yet */
.curr_chain_key = INITIAL_CHAIN_KEY,
.lockdep_recursion = 0,
#endif
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
2021-01-29 15:13:53 +00:00
.ret_stack = NULL,
.tracing_graph_pause = ATOMIC_INIT(0),
#endif
#if defined(CONFIG_TRACING) && defined(CONFIG_PREEMPTION)
.trace_recursion = 0,
#endif
#ifdef CONFIG_LIVEPATCH
.patch_state = KLP_UNDEFINED,
#endif
#ifdef CONFIG_SECURITY
.security = NULL,
#endif
#ifdef CONFIG_SECCOMP
.seccomp = { .filter_count = ATOMIC_INIT(0) },
#endif
};
2012-05-03 09:02:48 +00:00
EXPORT_SYMBOL(init_task);
/*
* Initial thread structure. Alignment of this is handled by a special
* linker map entry.
*/
#ifndef CONFIG_THREAD_INFO_IN_TASK
struct thread_info init_thread_info __init_thread_info = INIT_THREAD_INFO(init_task);
#endif