While doing it, also move all the code to resolve pathnames and obtain
text vp and dvp, into single place. Besides simplifying the code, it
avoids spurious vnode relocks and validates the explanation why
a transient text reference on the script vnode is not harmful.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D32611
For signal send, copyout from the user FPU save area directly.
For sigreturn, we are in sleepable context and can do temporal
allocation of the transient save area. We cannot copying from userspace
directly to user save area because XSAVE state needs to be validated,
also partial copyins can corrupt it.
Requested by: jhb
Reviewed by: jhb, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31954
Instead do one more allocation at the thread creation time. This frees
a lot of space on the stack.
Also do not use alloca() for temporal storage in signal delivery sendsig()
function and signal return syscall sys_sigreturn(). This saves equal
amount of space, again by the cost of one more allocation at the thread
creation time.
A useful experiment now would be to reduce KSTACK_PAGES.
Reviewed by: jhb, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D31954
Reimplement bdf0f24bb1 by checking for the caller' ABI in
the implementation of PT_GET_SC_ARGS, and copying out everything if
it is Linuxolator.
Also fix a minor information leak: if PT_GET_SC_ARGS_ALL is done on the
thread reused after other process, it allows to read some number of that
thread last syscall arguments. Clear td_sa.args in thread_alloc().
Reviewed by: jhb
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D31968
KMSAN enables the use of LLVM's MemorySanitizer in the kernel. This
enables precise detection of uses of uninitialized memory. As with
KASAN, this feature has substantial runtime overhead and is intended to
be used as part of some automated testing regime.
The runtime maintains a pair of shadow maps. One is used to track the
state of memory in the kernel map at bit-granularity: a bit in the
kernel map is initialized when the corresponding shadow bit is clear,
and is uninitialized otherwise. The second shadow map stores
information about the origin of uninitialized regions of the kernel map,
simplifying debugging.
KMSAN relies on being able to intercept certain functions which cannot
be instrumented by the compiler. KMSAN thus implements interceptors
which manually update shadow state and in some cases explicitly check
for uninitialized bytes. For instance, all calls to copyout() are
subject to such checks.
The runtime exports several functions which can be used to verify the
shadow map for a given buffer. Helpers provide the same functionality
for a few structures commonly used for I/O, such as CAM CCBs, BIOs and
mbufs. These are handy when debugging a KMSAN report whose
proximate and root causes are far away from each other.
Obtained from: NetBSD
Sponsored by: The FreeBSD Foundation
To prevent umtx.h polluting by future changes split it on two headers:
umtx.h - ABI header for userspace;
umtxvar.h - the kernel staff.
While here fix umtx_key_match style.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D31248
MFC after: 2 weeks
The syscall number is stored in the same register as the syscall return
on amd64 (and possibly other architectures) and so it is impossible to
recover in the signal handler after the call has returned. This small
tweak delivers it in the `si_value` field of the signal, which is
sufficient to catch capability violations and emulate them with a call
to a more-privileged process in the signal handler.
This reapplies 3a522ba1bc with a fix for
the static assertion failure on i386.
Approved by: markj (mentor)
Reviewed by: kib, bcr (manpages)
Differential Revision: https://reviews.freebsd.org/D29185
Instead of p_elf_machine use machine member of the Elf_Brandinfo which is now
cached in the struct proc at p_elf_brandinfo member.
Note to MFC: D30918, KBI
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D30926
MFC after: 2 weeks
To allow the ABI to make a dicision based on the Brandinfo add a link
to the Elf_Brandinfo into the struct proc. Add a note that the high 8 bits
of Elf_Brandinfo flags is private to the ABI.
Note to MFC: it breaks KBI.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D30918
MFC after: 2 weeks
It unsuspends single suspended thread, passed as the argument.
It is up to the caller to arrange the target thread to suspend later,
since the state of the process is not changed from stopped. In particular,
the unsuspended thread must not leave to userspace, since boundary code
is not prepared to this situation.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D29955
KCSAN complains about racy accesses in the locking code. Those races are
fine since they are inside a TD_SET_RUNNING() loop that expects the value
to be changed by another CPU.
Use relaxed atomic stores/loads to indicate that this variable can be
written/read by multiple CPUs at the same time. This will also prevent
the compiler from doing unexpected re-ordering.
Reported by: GENERIC-KCSAN
Test Plan: KCSAN no longer complains, kernel still runs fine.
Reviewed By: markj, mjg (earlier version)
Differential Revision: https://reviews.freebsd.org/D28569
Adding to zombie list can be perfomed by idle threads, which on ppc64 leads to
panics as it requires a sleepable lock.
Reported by: alfredo
Reviewed by: kib, markj
Fixes: r367842 ("thread: numa-aware zombie reaping")
Differential Revision: https://reviews.freebsd.org/D27288
The current global list is a significant problem, in particular induces a lot
of cross-domain thread frees. When running poudriere on a 2 domain box about
half of all frees were of that nature.
Patch below introduces per-domain thread data containing zombie lists and
domain-aware reaping. By default it only reaps from the current domain, only
reaping from others if there is free TID shortage.
A dedicated callout is introduced to reap lingering threads if there happens
to be no activity.
Reviewed by: kib, markj
Differential Revision: https://reviews.freebsd.org/D27185
No functional change intended.
Tracking these structures separately for each proc enables future work to
correctly emulate clone(2) in linux(4).
__FreeBSD_version is bumped (to 1300130) for consumption by, e.g., lsof.
Reviewed by: kib
Discussed with: markj, mjg
Differential Revision: https://reviews.freebsd.org/D27037
Since thread_zone is marked NOFREE the thread_fini callback is never
executed, meaning memory allocated by seltdinit is never released.
Adding the call to thread_dtor is not sufficient as exiting processes
cache the main thread.
This gets rid of the most contended spinlock seen when creating/destroying
threads in a loop. (modulo kstack)
Tested by: alfredo (ppc64), bdragon (ppc64)
Note this still does not scale but is enough to move it out of the way
for the foreseable future.
In particular a trivial benchmark spawning/killing threads stops contesting
on tidhash.
There are workloads with very bursty tid allocation and since unr tries very
hard to have small-sized bitmaps it keeps reallocating memory. Just doing
buildkernel gives almost 150k calls to free coming from unr.
This also gets rid of the hack which tried to postpone TID reuse.
Reviewed by: kib, markj
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D27101
The intent is to replace the current id allocation method and a known upper
bound will be useful.
Reviewed by: kib (previous version), markj (previous version)
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D27100
This avoids dirtying creds in the common case, see the comment in kern_prot.c
for details.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D24007
Previously we allocated a separate VM object for each kernel stack.
However, fully constructed kernel stacks are cached by UMA, so there is
no harm in using a single global object for all stacks. This reduces
memory consumption and makes it easier to define a memory allocation
policy for kernel stack pages, with the aim of reducing physical memory
fragmentation.
Add a global kstack_object, and use the stack KVA address to index into
the object like we do with kernel_object.
Reviewed by: kib
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24473
This NFS lock device driver was replaced by the kernel NLM around FreeBSD7 and
has not normally been used since then.
To use it, the kernel had to be built without "options NFSLOCKD" and
the nfslockd.ko had to be deleted as well.
Since it uses Giant and is no longer used, this patch removes it.
With this device driver removed, there is now a lot of unused code
in the userland rpc.lockd. That will be removed on a future commit.
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D22933
Modern debuggers and process tracers use ptrace() rather than procfs
for debugging. ptrace() has a supserset of functionality available
via procfs and new debugging features are only added to ptrace().
While the two debugging services share some fields in struct proc,
they each use dedicated fields and separate code. This results in
extra complexity to support a feature that hasn't been enabled in the
default install for several years.
PR: 244939 (exp-run)
Reviewed by: kib, mjg (earlier version)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D23837
Otherwise we can fail to handle translation faults on curthread, leading
to a panic.
Reviewed by: alc, rlibby
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23895
