this fixes the following deadlock.
a thread doing getcleanvnode:
pick a vnode
acqure v_interlock
v_usecount++
call vclean
now, another thread doing cache_lookup:
picks the vnode
vtryget succeed
vn_lock succeed
now in vclean:
set VI_XLOCK (too late to be noticed by the competing thread)
wait on the vnode lock (this might violate locking order)
the use of a flag bit was suggested by Andrew Doran. PR/41374.
Without it, on ports where splhigh() is inline, the compiler will optimise
the second SOFTINT_PENDING test in softint_schedule(). A dissasembly
of softint_schedule() with and without the volatile sh_flags confirm this
on sparc.
Because of this there is a race that could lead to the softhand_t
being enqueued twice on si_q, leading to a corrupted queue and
some handler being SOFTINT_PENDING but never called.
Should fix PR kern/38637
way they can be included without having to include DDB.
(arguably all print routines should be behind #ifdef DEBUGPRINT
and options DDB should define that macro, but I'll tackle that later)
a new struct mount-allocation routine, vfs_mountalloc(9). Documentation
updates will follow.
Attention: Synchronization Oversight Committee! In mount_domount(),
I postpone the call mutex_enter(&mp->mnt_updating) until right before
the VFS_MOUNT(9) call because (1) that looks to me like the earliest
possible opportunity for mp to become visible to any other LWP, because
it was just kmem_zalloc(9)'d and (2) it made extracting the common code
much easier. Tell me if my reasoning is faulty.
proc_enterpgrp() with proc_leavepgrp() to free process group and/or
session without proc_lock held.
- Rename SESSHOLD() and SESSRELE() to to proc_sesshold() and
proc_sessrele(). The later releases proc_lock now.
Quick OK by <ad>.
sometimes do not serve as memory barriers, allowing memory references to
bleed outside of critical sections. It's possible that this is the
reason for pkgbuild's longstanding crashiness.
For rwlocks, always enable the explicit membars. They were disabled only
on x86, and since they are not in the fast-path it's not a big deal.
TODO: convert these to an atomic_membar_foo() or similar that does ordering
between regular data references and atomic references.
- Add interrupt shielding (direct hardware interrupts away from the
specified CPUs). Not documented just yet but will be soon.
- Redo /dev/cpu time_t compat so no kernel changes are needed.
x86:
- Make intr_establish, intr_disestablish safe to use when !cold.
- Distribute hardware interrupts among the CPUs, instead of directing
everything to the boot CPU.
- Add MD code for interrupt sheilding. This works in most cases but there is
a bug where delivery is not accepted by an LAPIC after redistribution. It
also needs re-balancing to make things fair after interrupts are turned
back on for a CPU.
over and over to detach all of the devices. Stop when we cannot detach
even a single device in a cycle. Call shutdown hooks on all of the
devices that remain attached.
This is another step toward the detach/unmount cycle that will help us
tear down arbitrary stacks of filesystems, ccd(4), raid(4), and vnd(4).
filesystem at all, false otherwise. This will support tearing down
stacks of filesystems, ccd(4), raid(4), and vnd(4).
Change the misleading variable name 'allerror' to 'any_error'. Make it
a bool.
don't forget to set m_len to 0. Otherwise whatever will compute the size
of this chain (including s_split() itself if called again on this chain)
will get it wrong, leading to various issues.
Bug exposed by the NFS server code with linux clients using TCP mounts.
than one active reference to a file descriptor. It should dislodge threads
sleeping while holding a reference to the descriptor. Implemented only for
sockets but should be extended to pipes, fifos, etc.
Fixes the case of a multithreaded process doing something like the
following, which would have hung until the process got a signal.
thr0 accept(fd, ...)
thr1 close(fd)
provided is "too large" (log10(2^64) = 19).
(It can still overflow if the input value is close to 2^64 but I don't
consider this a problem.)
fixes nonsense displayed as "total memory" on boot
Call the detach routine for every device in the device tree, starting
with the leaves and moving toward the root, expecting that each
(pseudo-)device driver will use the opportunity to gracefully commit
outstandings transactions to the underlying (pseudo-)device and to
relinquish control of the hardware to the system BIOS.
Detaching devices is not suitable for every shutdown: in an emergency,
or if the system state is inconsistent, we should resort to a fast,
simple shutdown that uses only the pmf(9) shutdown hooks and the
(deprecated) shutdownhooks. For now, if the flag RB_NOSYNC is set in
boothowto, opt for the fast, simple shutdown.
Add a device flag, DVF_DETACH_SHUTDOWN, that indicates by its presence
that it is safe to detach a device during shutdown. Introduce macros
CFATTACH_DECL3() and CFATTACH_DECL3_NEW() for creating autoconf
attachments with default device flags. Add DVF_DETACH_SHUTDOWN
to configuration attachments for atabus(4), atw(4) at cardbus(4),
cardbus(4), cardslot(4), com(4) at isa(4), elanpar(4), elanpex(4),
elansc(4), gpio(4), npx(4) at isa(4), nsphyter(4), pci(4), pcib(4),
pcmcia(4), ppb(4), sip(4), wd(4), and wdc(4) at isa(4).
Add a device-detachment "reason" flag, DETACH_SHUTDOWN, that tells the
autoconf code and a device driver that the reason for detachment is
system shutdown.
Add a sysctl, kern.detachall, that tells the system to try to detach
every device at shutdown, regardless of any device's DVF_DETACH_SHUTDOWN
flag. The default for kern.detachall is 0. SET IT TO 1, PLEASE, TO
HELP TEST AND DEBUG DEVICE DETACHMENT AT SHUTDOWN.
This is a work in progress. In future work, I aim to treat
pseudo-devices more thoroughly, and to gracefully tear down a stack of
(pseudo-)disk drivers and filesystems, including cgd(4), vnd(4), and
raid(4) instances at shutdown.
Also commit some changes that are not easily untangled from the rest:
(1) begin to simplify device_t locking: rename struct pmf_private to
device_lock, and incorporate device_lock into struct device.
(2) #include <sys/device.h> in sys/pmf.h in order to get some
definitions that it needs. Stop unnecessarily #including <sys/device.h>
in sys/arch/x86/include/pic.h to keep the amd64, xen, and i386 releases
building.
This will be used to support TLS. The MD method must match the ELF TLS spec
for that CPU architecture (if there is a spec).
At this time it is only implemented for i386, where it means setting the
per-thread base address for %gs. Please implement this for your platform!
signals (i.e. SA_KILL), just if SIGKILL (or SIGCONT). Improve comments.
Make some functions static, remove unused sigrealloc() prototype.
Fixes PR/39814. Similar patch reviewed by <ad>.
address space available to processes. this limit exists in most other
modern unix variants, and like most of them, our defaults are unlimited.
remove the old mmap / rlimit.datasize hack.
- adds the VMCMD_STACK flag to all the stack-creation vmcmd callers.
it is currently unused, but was added a few years ago.
- add a pair of new process size values to kinfo_proc2{}. one is the
total size of the process memory map, and the other is the total size
adjusted for unused stack space (since most processes have a lot of
this...)
- patch sh, and csh to notice RLIMIT_AS. (in some cases, the alias
RLIMIT_VMEM was already present and used if availble.)
- patch ps, top and systat to notice the new k_vm_vsize member of
kinfo_proc2{}.
- update irix, svr4, svr4_32, linux and osf1 emulations to support
this information. (freebsd could be done, but that it's best left
as part of the full-update of compat/freebsd.)
this addresses PR 7897. it also gives correct memory usage values,
which have never been entirely correct (since mmap), and have been
very incorrect since jemalloc() was enabled.
tested on i386 and sparc64, build tested on several other platforms.
thanks to many folks for feedback and testing but most espcially
chuq and yamt for critical suggestions that lead to this patch not
having a special ugliness i wasn't happy with anyway :-)
There are also sigtimedwait(2) et al. to catch signals without invoking
a signal handler. Fixes PR kern/41076 by Matteo Beccati (the first
test case, where the signal is sent before sigwaitinfo(2) gets called).
Fix numerous problems:
1. LDT updates are not atomic.
2. Number of processes running with private LDTs and/or I/O bitmaps
is not capped. System with high maxprocs can be paniced.
3. LDTR can be leaked over context switch.
4. GDT slot allocations can race, giving the same LDT slot to two procs.
5. Incomplete interrupt/trap frames can be stacked.
6. In some rare cases segment faults are not handled correctly.
There are still about 1600 left, but they have ',' or /* ... */
in the actual variable definitions - which my awk script doesn't handle.
There are also many that need () -> (void).
(The script does handle misordered arguments.)
via SCM_RIGHTS messages are dealt with:
1. unp_gc: make this a kthread.
2. unp_detach: go not call unp_gc directly. instead, wake up unp_gc kthread.
3. unp_scan: do not close files here. instead, put them on a global list
for unp_gc to close, along with a per-file "deferred close count". if
file is already enqueued for close, just increment deferred close count.
this eliminates the recursive calls.
3. unp_gc: scan files on global deferred close list. close each file N
times, as specified by deferred close count in file. continue processing
list until it becomes empty (closing may cause additional files to be
queued for close).
4. unp_gc: add additional bit to mark files we are scanning. set during
initial scan of global file list that currently clears FMARK/FDEFER.
during later scans, never examine / garbage collect descriptors that
we have not marked during the earlier scan. do not proceed with this
initial scan until all deferred closes have been processed. be careful
with locking to ensure no races are introduced between deferred close
and file scan.
5. unp_gc: use dummy file_t to mark position in list when scanning. allow
us to drop filelist_lock. in turn allows us to eliminate kmem_alloc()
and safely close files, etc.
6. prohibit transfer of descriptors within SCM_RIGHTS messages if
(num_files_in_transit > maxfiles / unp_rights_ratio)
7. fd_allocfile: ensure recycled filse don't get scanned.
this is 97% work done by andrew doran, with a couple of minor bug fixes
and a lot of testing by yours truly.
PR kern/16942 panic with softdep and quotas
PR kern/19565 panic: softdep_write_inodeblock: indirect pointer #1 mismatch
PR kern/26274 softdep panic: allocdirect_merge: ...
PR kern/26374 Long delay before non-root users can write to softdep partitions
PR kern/28621 1.6.x "vp != NULL" panic in ffs_softdep.c:4653 while unmounting a softdep (+quota) filesystem
PR kern/29513 FFS+Softdep panic with unfsck-able file-corruption
PR kern/31544 The ffs softdep code appears to fail to write dirty bits to disk
PR kern/31981 stopping scsi disk can cause panic (softdep)
PR kern/32116 kernel panic in softdep (assertion failure)
PR kern/32532 softdep_trackbufs deadlock
PR kern/37191 softdep: locking against myself
PR kern/40474 Kernel panic after remounting raid root with softdep
Retire softdep, pass 2. As discussed and later formally announced on the
mailing lists.
PR kern/40361 WAPBL locking panic in -current
PR kern/40361 WAPBL locking panic in -current
PR kern/40470 WAPBL corrupts ext2fs
PR kern/40562 busy loop in ffs_sync when unmounting a file system
PR kern/40525 panic: ffs_valloc: dup alloc
- A fix for an issue that can lead to "ffs_valloc: dup" due to dirty cg
buffers being invalidated. Problem discovered and patch by dholland@.
- If the syncer fails to lazily sync a vnode due to lock contention,
retry 1 second later instead of 30 seconds later.
- Flush inode atime updates every ~10 seconds (this makes most sense with
logging). Presently they didn't hit the disk for read-only files or
devices until the file system was unmounted. It would be better to trickle
the updates out but that would require more extensive changes.
- Fix issues with file system corruption, busy looping and other nasty
problems when logging and non-logging file systems are intermixed,
with one being the root file system.
- For logging, do not flush metadata on an inode-at-a-time basis if the sync
has been requested by ioflush. Previously, we could try hundreds of log
sync operations a second due to inode update activity, causing the syncer
to fall behind and metadata updates to be serialized across the entire
file system. Instead, burst out metadata and log flushes at a minimum
interval of every 10 seconds on an active file system (happens more often
if the log becomes full). Note this does not change the operation of
fsync() etc.
- With the flush issue fixed, re-enable concurrent metadata updates in
vfs_wapbl.c.
backend, perform all calls through a syscall table. This makes it
possible to make system calls to non-local rump kernels.
(requires a bit support code. it's written but quite messy currently)
- reimplement vmem sanity checks with less code duplication.
- reimplement ddb vmem-related commands in a more consistent ways.
remove automatic whatis.
it caused the return from the enclosing function to break, as well as the
ssp return on i386. To fix both issues, split configure in two pieces
the one before calling ssp_init and the one after, and move the ssp_init()
call back in main. Put ssp_init() in its own file, and compile this new file
with -fno-stack-protector. Tested on amd64.
XXX: If we want to have ssp kernels working on 5.0, this change needs to
be pulled up.
- NOCHROOT flag must be assigned to different bit from TRYEMULROOT
since the code expected to be executed is in the else clase of
if (flags & TRYEMULROOT).
- Necessary variables aren't set.
