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path: root/sys/kern/kern_sig.c
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2022-03-11Revert part of rev 1.293. Using cursig() to deliver masked signalsClaudio Jeker
to the debugger can cause a loop between the debugger and cursig() if the signal is masked. cursig() has no way to know which signal was already delivered to the debugger and so it delivers the same signal over and over again. Instead handle traps to masked signals directly in trapsignal. This is what rev 1.293 was mostly about. If SIGTRAP was masked by the process breakpoints no longer worked since the signal deliver to the debugger did not happen. Doing this case in trapsignal solves both the problem with the loop and the delivery of masked traps. Problem reported and fix tested by matthieu@ OK kettenis@ mpi@
2022-02-14Introduce a signal context that is used to pass signal related informationClaudio Jeker
from cursig() to postsig() or the caller itself. This will simplify locking. Also alter sigactsfree() a bit and move it into process_zap() so ps_sigacts is always a valid pointer. OK semarie@
2022-02-06Simplify cursig() a bit and make sure that signals are always sent toClaudio Jeker
the parent of ptraced processes. Especially ignore the signal mask set by sigprocmask(2) in that case. In userret() alter the testcase for when to call cursig() which is only there to avoid taking the KERNEL_LOCK when returning from a MP safe syscall. This can be revisited once cursig() is MP safe. Problem with debugging signal handlers found by kurt@ Tested and OK kurt@, OK mpi@
2022-01-02immediatly -> immediatelyTheo Buehler
2021-12-07Delete the last emulation callbacks: we're Just ELF, so declarePhilip Guenther
exec_elf_fixup() and coredump_elf() in <sys/exec_elf.h> and call them and the MD setregs() directly in kern_exec.c and kern_sig.c Also delete e_name[] (only used by sysctl), e_errno (unused), and e_syscallnames[] (only used by SYSCALL_DEBUG) and constipate syscallnames to 'const char *const[]' ok kettenis@
2021-11-24Refactor postsig_done(). Pass the catchmask and signal reset flag to theClaudio Jeker
function. This will make unlocking cursig() & postsig() a bit easier. OK mpi@
2021-11-24Minor code cleanup. Move a comment to the right place, move a functionClaudio Jeker
to get a better order of functions. Also reduce the size of sigprop to NSIG from NSIG+1. NSIG is defined as 33 and so includes the extra element for this array. OK mpi@
2021-11-12sigsuspend(2): sleep on &nowake channelScott Soule Cheloha
sigsuspend(2) only returns upon delivery of a signal: we do not expect a wakeup(9). Indicate this by sleeping on &nowake instead of &p->p_p->ps_sigacts. We still need to loop here to handle spurious wakeups, though. Spurious wakeup case pointed out by kettenis@. ok claudio@
2021-10-24use NULL not 0 for pointer values in kernJonathan Gray
ok semarie@
2021-10-23Be consistend and add missing spaces around some of the NOTREACHED comments.Claudio Jeker
2021-10-06Change sendsig() interface so that the MD code does not need to accessClaudio Jeker
data from struct process anymore. This changes how siginfo and onstack are accessed and make sendsig() more MP friendly. With and OK semarie@ OK kettenis@
2021-10-04Simplify sys___thrsigdivert a bit. cursig() always moves the pending signalClaudio Jeker
to p_siglist and so there is no need to check ps_siglist for the signal. OK mpi@
2021-09-28Fix timeout behaviour bug introduced in 1.241.Claudio Jeker
If the timespec is zero-valued sys___thrsigdivert() should just do the check for pending signals and return immediatly. OK kettenis@
2021-07-14After VFS shutdown, init(8) cannot map a missing page that containsAlexander Bluhm
the signal handler code. Traditionally a process would spin in such a case, but we changed the logic in revision 1.167 trapsignal() to receive a fatal signal. If that happens to init(8), the kernel panics. In case of reboot, jump between init signal handler and page fault trap until the kernel resets the machine. reported and tested weerd@; OK deraadt@
2021-05-10Revert previous, it introduced a regression with breakpoints in gdb.Martin Pieuchot
2021-05-06Refactor routines to stop/unstop processes and save the corresponding signal.Martin Pieuchot
- Move the "hack" involving P_SINTR to avoid grabbing the SCHED_LOCK() recursively closer to where it is necessary, in proc_stop() - Introduce proc_unstop(), the symmetric routine to proc_stop(), which manipulates `ps_xsig' and use it whenever a SSTOPed thread needs to be awaken. - Manipulate `ps_xsig' only in proc_stop/unstop() ok kettenis@
2021-03-21Use uppercases for defines.Martin Pieuchot
No functional change. ok semarie@
2021-03-12Kill SINGLE_PTRACE and use SINGLE_SUSPEND which has almost the same semanticMartin Pieuchot
single_thread_set() is modified to explicitly indicated when waiting until sibling threads are parked is required. This is obviously not required if a traced thread is switching away from a CPU after handling a STOP signal. ok claudio@
2021-03-08Revert commitid: AZrsCSWEYDm7XWuv;Claudio Jeker
Kill SINGLE_PTRACE and use SINGLE_SUSPEND which has almost the same semantic. This diff did not properly kill SINGLE_PTRACE and broke RAMDISK kernels.
2021-03-08Move a KERNEL_ASSERT_LOCKED() from single_thread_clear() to cursig().Martin Pieuchot
Ze big lock is currently necessary to ensure that two sibling threads are not racing against each other when processing signals. However it is not strickly necessary to unpark sibling threads. ok claudio@
2021-03-08Kill SINGLE_PTRACE and use SINGLE_SUSPEND which has almost the same semantic.Martin Pieuchot
single_thread_set() is modified to explicitly indicated when waiting until sibling threads are parked is required. This is obviously not required if a traced thread is switching away from a CPU after handling a STOP signal. ok claudio@
2021-03-04Merge issignal() and CURSIG() in preparation for turning it mp-safe.Martin Pieuchot
This makes appear some redundant & racy checks. ok semarie@
2021-02-15Move single_thread_set() out of KERNEL_LOCK().Martin Pieuchot
Use the SCHED_LOCK() to ensure `ps_thread' isn't being modified by a sibling when entering tsleep(9) w/o KERNEL_LOCK(). ok visa@
2021-02-08Revert the convertion of per-process thread into a SMR_TAILQ.Martin Pieuchot
We did not reach a consensus about using SMR to unlock single_thread_set() so there's no point in keeping this change.
2021-02-08Simplify sleep_setup API to two operations in preparation for splittingMartin Pieuchot
the SCHED_LOCK(). Putting a thread on a sleep queue is reduce to the following: sleep_setup(); /* check condition or release lock */ sleep_finish(); Previous version ok cheloha@, jmatthew@, ok claudio@
2020-12-25Refactor klist insertion and removalVisa Hankala
Rename klist_{insert,remove}() to klist_{insert,remove}_locked(). These functions assume that the caller has locked the klist. The current state of locking remains intact because the kernel lock is still used with all klists. Add new functions klist_insert() and klist_remove() that lock the klist internally. This allows some code simplification. OK mpi@
2020-12-23sigsuspend(2): change wmesg from "pause" to "sigsusp"cheloha
Make it obvious where the thread is blocked. "pause" is ambiguous. Tweaked by kettenis@. Probably ok kettenis@.
2020-12-07Convert the per-process thread list into a SMR_TAILQ.Martin Pieuchot
Currently all iterations are done under KERNEL_LOCK() and therefor use the *_LOCKED() variant. From and ok claudio@
2020-12-04Prevent a TOCTOU race in single_thread_set() by extending the scope of the lock.Martin Pieuchot
Make sure `ps_single' is set only once by checking then updating it without releasing the lock. Analyzed by and ok claudio@
2020-12-02Revert previous extension of the SCHED_LOCK(), the state isn't passed down.Martin Pieuchot
Panic reported by dhill@
2020-12-02Prevent a TOCTOU race in single_thread_set() by extending the scope of the lock.Martin Pieuchot
Make sure `ps_single' is set only once by checking then updating it without releasing the lock. Analyzed by and ok claudio@
2020-11-08In case of failure, call sigexit() from trapsignal instead of sensig().Martin Pieuchot
Simplify MD code and reduce the amount of recursion into the signal code which helps when dealing with locks. ok cheloha@, deraadt@
2020-09-16Move duplicated code to send an uncatchable SIGABRT into a function.Martin Pieuchot
ok claudio@
2020-09-13Unbreak tree. Instead of passing struct process to siginit() just pass theClaudio Jeker
struct sigacts since that is the only thing that is modified by siginit.
2020-09-09Introduce a helper to check if a signal is ignored or masked by a thread.Martin Pieuchot
ok claudio@, pirofti@
2020-08-26Fix a race in single-thread mode switchingVisa Hankala
Extend the scope of SCHED_LOCK() to better synchronize single_thread_set(), single_thread_clear() and single_thread_check(). This prevents threads from suspending before single_thread_set() has finished. If a thread suspended early, ps_singlecount might get decremented too much, which in turn could make single_thread_wait() get stuck. The race could be triggered for example by trying to stop a multithreaded process with a debugger. When triggered, the race prevents the debugger from finishing a wait4(2) call on the debuggee. This kind of gdb hang was reported by Julian Smith on misc@. Unfortunately, single-thread mode switching still has issues and hangs are still possible. OK mpi@
2020-08-19Push KERNEL_LOCK/UNLOCK() dance inside trapsignal().Martin Pieuchot
ok kettenis@, visa@
2020-06-15Raise SPL when modifying ps_klist to prevent a race with interrupts.Visa Hankala
The list can be accessed from interrupt context if a signal is sent from an interrupt handler. OK anton@ cheloha@ mpi@
2020-06-14Remove misleading XXX about locking of ps_klist. All of the kqueueVisa Hankala
subsystem and ps_klist handling still run under the kernel lock.
2020-04-07Abstract the head of knote lists. This allows extending the lists,Visa Hankala
for example, with locking assertions. OK mpi@, anton@
2020-03-20Use atomic operations to update ps_singlecount. This makesClaudio Jeker
single_thread_check() safe to be called without KERNEL_LOCK(). single_thread_wait() needs to use sleep_setup() and sleep_finish() instead of tsleep() to make sure no wakeup() is lost. Input kettenis@, with and OK visa@
2020-03-18Restart child process scan in dowait4() if single_thread_wait() sleeps.Visa Hankala
This ensures that the conditions checked are still in force. The sleep breaks atomicity, allowing another thread to alter the state. single_thread_set() should return immediately after sleep when called from dowait4() because there is no guarantee that the process pr still exists. When called from single_thread_set(), the process is that of the calling thread, which prevents process pr from disappearing. OK anton@, mpi@, claudio@
2020-03-13Rename "sigacts" flag field to avoid conflict with the "process" one.Martin Pieuchot
This shows that atomic_* operations should not be necessery to write to this field unlike with the process one. The advantage of using a somewhat-unique prefix for struct member is moot when multiple definitions use the same prefix :o) From Amit Kulkarni, ok claudio@
2020-03-11Move the sigprop definition and the other bits under SIGPROP intoClaudio Jeker
kern_sig.c where they are currently added by the include. While doing that mark the sigprop array as const. OK mpi@ anton@ millert@
2020-02-21Remove sigacts structure sharing. The only process that used sharing wasClaudio Jeker
proc0 which is used for kthreads and idle threads. proc0 and all those other kernel threads don't handle signals so there is no benefit in sharing. Simplifies the code a fair bit since the refcnt is gone. OK kettenis@
2020-02-21Adjust a comment, no functional changeClaudio Jeker
2020-02-20Replace field f_isfd with field f_flags in struct filterops to allowVisa Hankala
adding more filter properties without cluttering the struct. OK mpi@, anton@
2020-02-19Remove the indirection via timeout for proc_stop_sweep(). Using a softClaudio Jeker
interrupt is enough to defer the signal handling. This is a leftover from the times where not all archs had generic soft interrupts. It is possible that the defer signal handling to a soft interrupt will be removed at a later stage. Input anton@, mpi@ OK kettenis@
2020-02-15Consistently perform atomic writes to the ps_flags field of structanton
process. ok bluhm@ claudio@ visa@
2020-02-14Push the KERNEL_LOCK() insidge pgsigio() and selwakeup().Martin Pieuchot
The 3 subsystems: signal, poll/select and kqueue can now be addressed separatly. Note that bpf(4) and audio(4) currently delay the wakeups to a separate context in order to respect the KERNEL_LOCK() requirement. Sockets (UDP, TCP) and pipes spin to grab the lock for the sames reasons. ok anton@, visa@
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