freebsd-skq/sys/kern
kib e18e95605f Don't clear the software flow control flag before draining for last
close or assert the bug that it is clear when leaving.

Remove an unrelated rotted comment that was attached to the buggy
clearing.

Since draining is not done in more cases, flushing is needed in more
cases, so start fixing flushing:
- do a full flush in ttydisc_close().  State what POSIX requires more
  clearly.  This was missing ttydevsw_pktnotify() calls to tell the
  devsw layer to flush.  Hardware tty drivers don't actually flush
  since they don't understand this API.
- fix 2 missing wakeups in tty_flush().  Most of the wakeups here are
  unnecessary for last close.  But ttydisc_close() did one of the
  missing ones.

This flow control bug ameliorated the design bug of requiring
potentially unbounded waits in draining.  Software flow control is the
easiest way to get an unbounded wait, and a long wait is sometimes
actually useful.  Users can type the xoff character on the receiver
and (if ixon is set on the sender) expect the output to be held until
the user is ready for more.

Hardware flow control can also give the unbounded wait, and this bug
didn't affect hardware flow control.  Unbounded waits from hardware
flow control take a more unusual configuration.  E.g., a terminal
program that controls the modem status lines, or unplugging the cable
in a configuration where this doesn't break the connection.

The design bug is still ameliorated by a newer bug in draining for
last close -- the 1 second timeout.  E.g., if the user types the
xoff character and the sender reaches last close, then output is
not resumed and the wait times out after just 1 second.  This is
broken, but preferable to an unbounded wait.  Before this change,
the output was resumed immediately and usually completed.

Submitted by:	bde
MFC after:	2 weeks
2016-01-26 14:46:39 +00:00
..
bus_if.m Add a note to the effect that BUS_ADD_CHILD calls 2015-10-28 18:53:18 +00:00
capabilities.conf Add futimens and utimensat system calls. 2015-01-23 21:07:08 +00:00
clock_if.m
cpufreq_if.m
device_if.m Change the default method for device_quiesce() to return 0 instead of 2015-01-08 21:46:28 +00:00
genassym.sh genassym.sh: call nm(1) with NMFLAGS. 2015-08-14 22:57:13 +00:00
imgact_aout.c Implement vsyscall hack. Prior to 2.13 glibc uses vsyscall 2016-01-09 20:18:53 +00:00
imgact_binmisc.c At the suggestion of jhb, replace atomic_set/clear calls with use of 2015-06-24 15:52:26 +00:00
imgact_elf32.c
imgact_elf64.c
imgact_elf.c Do not substitute interpeter if the brand interpreter path is 2015-12-26 15:40:12 +00:00
imgact_gzip.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
imgact_shell.c Allow multiple image activators to run on the same execution by changing 2014-09-04 21:31:25 +00:00
inflate.c
init_main.c Implement vsyscall hack. Prior to 2.13 glibc uses vsyscall 2016-01-09 20:18:53 +00:00
init_sysent.c Missing regen after last change to sys/kern/syscalls.master. 2015-10-22 21:30:39 +00:00
kern_acct.c
kern_alq.c Prevent alq from panic when the invalid alq_file path specified. 2014-04-05 16:54:47 +00:00
kern_clock.c Initialize ticks so that it wraps 10 minutes after boot to increase the 2015-02-05 01:43:21 +00:00
kern_clocksource.c Fix typo in comment. 2015-07-20 09:37:42 +00:00
kern_condvar.c Prevent cv_waiters wraparound. 2016-01-09 01:56:46 +00:00
kern_conf.c Provide yet another KPI for cdev creation, make_dev_s(9). 2016-01-07 20:08:02 +00:00
kern_cons.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
kern_context.c
kern_cpu.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_cpuset.c Un-static cpuset_which() - it's useful in other contexts, such as some 2015-06-26 04:14:05 +00:00
kern_ctf.c Don't specify a resid parameter if we're just going to ignore it. Instead, 2015-02-20 20:49:00 +00:00
kern_descrip.c fd: implement kern.proc.nfds sysctl 2015-11-07 00:18:14 +00:00
kern_dtrace.c Commit the rest of the changes that were intended to be part of r266826. 2014-05-29 01:42:22 +00:00
kern_dump.c - Unbreak dumpsys(9) on sparc64 after r276772 2015-11-16 23:02:33 +00:00
kern_environment.c Make the 'env' directive described in config(5) work on all architectures, 2016-01-02 02:53:48 +00:00
kern_et.c Trivial change / forced-commit to document prior change that slipped in 2015-03-16 19:29:19 +00:00
kern_event.c kqueue: simplify kern_kqueue by not refing/unrefing creds too early 2015-09-23 12:45:08 +00:00
kern_exec.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_exit.c session: avoid proctree lock on proc exit when possible 2016-01-20 23:33:58 +00:00
kern_fail.c Use a regular sbuf + SYSCTL_OUT() rather than sbuf_new_for_sysctl() with 2015-03-16 19:18:45 +00:00
kern_ffclock.c The SYSCTL data pointers can come from userspace and must not be 2014-10-28 12:00:39 +00:00
kern_fork.c Add ptrace(2) reporting for LWP events. 2015-12-29 23:25:26 +00:00
kern_gzio.c Move zlib.c from net to libkern. 2015-04-22 14:38:58 +00:00
kern_hhook.c Check that hhk_helper pointer isn't NULL before access. 2015-11-25 07:14:58 +00:00
kern_idle.c
kern_intr.c The part of r285680 which removed release semantic for two stores to 2015-07-21 14:39:34 +00:00
kern_jail.c Fix jail name checking that disallowed anything that starts with '0'. 2015-12-15 17:25:00 +00:00
kern_khelp.c
kern_kthread.c Limit rights on process descriptors. 2015-07-31 10:21:58 +00:00
kern_ktr.c - (Ab)use udivx for dividing the u_int pc_cpuid when implementing 2015-12-30 13:49:20 +00:00
kern_ktrace.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_linker.c Create the MDT_PNP_INFO metadata record to communicate PNP info about 2015-12-11 05:27:53 +00:00
kern_lock.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_lockf.c Improve style and fix a possible use-after-free case introduced in r268384 2015-01-10 06:48:35 +00:00
kern_lockstat.c Consistently use a reader/writer flag for lockstat probes in rwlock(9) and 2015-07-19 22:24:33 +00:00
kern_loginclass.c Speed up rctl operation with large rulesets, by holding the lock 2015-11-15 12:10:51 +00:00
kern_malloc.c Don't make assertions about td_critnest when the scheduler is stopped. 2015-12-11 20:05:07 +00:00
kern_mbuf.c Add a safety net to reclaim mbufs when one of the mbuf zones become 2015-12-20 02:05:33 +00:00
kern_mib.c Export various helper variables describing the layout and size of 2015-11-12 22:00:59 +00:00
kern_module.c Provide better debug message on kernel module name clash. 2015-10-10 09:21:55 +00:00
kern_mtxpool.c Garbage collect mtxpool_lockbuilder, the mutex pool historically used 2014-05-02 07:57:40 +00:00
kern_mutex.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_ntptime.c Use the monotonic (uptime) counter rather than time-of-day to measure elapsed 2015-07-12 18:38:17 +00:00
kern_numa.c Add an initial NUMA affinity/policy configuration for threads and processes. 2015-07-11 15:21:37 +00:00
kern_osd.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_physio.c Add missing NULL check in physio(). 2015-10-29 13:53:37 +00:00
kern_pmc.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_poll.c When a kernel has DEVICE_POLLING turned on but no drivers have 2015-04-14 14:22:34 +00:00
kern_priv.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
kern_proc.c session: avoid proctree lock on proc exit when possible 2016-01-20 23:33:58 +00:00
kern_procctl.c If process becomes reaper (procctl(PROC_REAP_ACQUIRE)) while already 2015-08-20 22:44:26 +00:00
kern_prot.c Call crextend() before copying old credentials to the new credentials 2016-01-14 10:16:25 +00:00
kern_racct.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_rangelock.c
kern_rctl.c Fix the way RCTL handles rules' rrl_exceeded on credenials change. 2016-01-26 11:28:55 +00:00
kern_resource.c Fold lim_shared into lim_copy to mute a -Wunused compiler warning from 2015-12-22 21:07:33 +00:00
kern_rmlock.c Threads holding a read lock of a sleepable rm lock are not permitted 2015-09-15 22:16:21 +00:00
kern_rwlock.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_sdt.c Print a backtrace if the SDT(9) stub gets called so that there's at least 2014-02-22 01:41:45 +00:00
kern_sema.c
kern_sendfile.c - Separate sendfile(2) implementation from uipc_syscalls.c into 2016-01-22 02:23:18 +00:00
kern_sharedpage.c Split kerne timekeep ABI structure vdso_sv_tk out of the struct 2015-11-23 07:09:35 +00:00
kern_shutdown.c Disable suspend when we're shutting down. This solves the "tell FreeBSD 2015-10-01 10:52:26 +00:00
kern_sig.c Add ptrace(2) reporting for LWP events. 2015-12-29 23:25:26 +00:00
kern_switch.c Revert for r277213: 2015-01-22 11:12:42 +00:00
kern_sx.c Don't modify curthread->td_locks unless INVARIANTS is enabled. 2015-08-02 00:03:08 +00:00
kern_synch.c Remove several write-only variables, all reported by the gcc 4.9 2015-05-29 13:24:17 +00:00
kern_syscalls.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
kern_sysctl.c Evaluate the sysctl_running fail point before taking the sysctl lock. 2016-01-26 01:15:18 +00:00
kern_tc.c Define fhard in pps_event(..) only when PPS_SYNC is defined to mute 2015-11-02 03:14:37 +00:00
kern_thr.c Add ptrace(2) reporting for LWP events. 2015-12-29 23:25:26 +00:00
kern_thread.c Call kern_thr_exit() instead of duplicating it. 2015-12-29 23:16:20 +00:00
kern_time.c Verify that tv_sec value specified in settimeofday() and clock_settime() 2015-12-27 15:37:07 +00:00
kern_timeout.c Fix style issues around existing SDT probes. 2015-12-16 23:39:27 +00:00
kern_umtx.c Minor (and incomplete) style cleanup. 2015-10-30 20:47:42 +00:00
kern_uuid.c Fix a bug in be_uuid_dec(); it called le16dec() instead of be16dec(), 2014-02-13 22:24:36 +00:00
kern_xxx.c
ksched.c Use P1B_PRIO_MAX to designate max posix priority for the RR/FIFO 2015-08-30 18:02:57 +00:00
link_elf_obj.c Add support for weak symbols to the kernel linkers. It means that 2015-09-20 01:27:59 +00:00
link_elf.c Fix r292640 2015-12-23 03:34:43 +00:00
linker_if.m
Make.tags.inc Bring the tags and links entries for amd64 up to date. 2015-10-27 22:59:24 +00:00
Makefile
makesyscalls.sh Rename remaining linux32 symbols such as linux_sysent[] and 2015-10-22 21:28:20 +00:00
md4c.c
md5c.c
p1003_1b.c In preparation for switching linuxulator to the use the native 1:1 2015-05-24 14:44:06 +00:00
pic_if.m [intrng] Migrate the intrng code from sys/arm/arm to sys/kern/subr_intr.c. 2015-12-18 05:43:59 +00:00
posix4_mib.c
sched_4bsd.c kgdb uses td_oncpu to determine if a thread is running and should use 2015-08-03 20:43:36 +00:00
sched_ule.c Summary: Add the interactivity equations to the header comment for our 2015-08-26 16:36:41 +00:00
serdev_if.m
stack_protector.c Use nitems() macro instead of __arraycount() 2015-06-16 20:19:00 +00:00
subr_acl_nfs4.c Expose an interface to determine if an ACE is inherited. 2015-09-04 00:14:20 +00:00
subr_acl_posix1e.c
subr_autoconf.c
subr_blist.c
subr_bufring.c
subr_bus_dma.c Fix a bug introduced in r291716: 2016-01-11 20:38:39 +00:00
subr_bus.c Huge cleanup of random(4) code. 2015-06-30 17:00:45 +00:00
subr_busdma_bufalloc.c Fix printf format to allow for bus_size_t not being u_long on all platforms. 2015-10-20 03:25:17 +00:00
subr_capability.c capsicum: plug spurious memset in __cap_rights_init 2015-12-01 02:48:42 +00:00
subr_clock.c For architectures where time_t is wide enough, in particular, 64bit 2014-12-12 09:37:18 +00:00
subr_counter.c Create two public UMA_ZONE_PCPU zones: 64 bit sized and pointer sized. 2014-02-10 19:59:46 +00:00
subr_devstat.c Fix multiple incorrect SYSCTL arguments in the kernel: 2014-10-21 07:31:21 +00:00
subr_disk.c
subr_dummy_vdso_tc.c Update the vdso timehands only via tc_windup(). 2015-01-20 03:54:30 +00:00
subr_eventhandler.c
subr_fattime.c Where appropriate, use the modern terms for the one true time base 2014-12-21 05:07:11 +00:00
subr_firmware.c Create a dedicated function for ensuring that cdir and rdir are populated. 2015-07-11 16:22:48 +00:00
subr_hash.c
subr_hints.c Add a new device control utility for new-bus devices called devctl. This 2015-02-06 16:09:01 +00:00
subr_intr.c [intrng] Migrate the intrng code from sys/arm/arm to sys/kern/subr_intr.c. 2015-12-18 05:43:59 +00:00
subr_kdb.c Fix multiple incorrect SYSCTL arguments in the kernel: 2014-10-21 07:31:21 +00:00
subr_kobj.c
subr_lock.c Add _NEW flag to mtx(9), sx(9), rmlock(9) and rwlock(9). 2014-12-13 21:00:10 +00:00
subr_log.c
subr_mbpool.c All mbuf external free functions never fail, so let them be void. 2014-07-11 13:58:48 +00:00
subr_mchain.c
subr_module.c preload_search_info: make sure mod is set 2015-08-21 15:57:57 +00:00
subr_msgbuf.c Pull in r267961 and r267973 again. Fix for issues reported will follow. 2014-06-28 03:56:17 +00:00
subr_param.c Ensure that maxproc does not exceed pid_max, at the time of boot. 2015-09-21 15:02:59 +00:00
subr_pcpu.c Create two public UMA_ZONE_PCPU zones: 64 bit sized and pointer sized. 2014-02-10 19:59:46 +00:00
subr_pctrie.c
subr_power.c
subr_prf.c Add vlog(9). 2015-11-19 05:50:22 +00:00
subr_prof.c The process spin lock currently has the following distinct uses: 2014-11-26 14:10:00 +00:00
subr_rman.c When dumping an rman in DDB, include the RID of each resource. 2015-11-05 23:12:23 +00:00
subr_rtc.c
subr_sbuf.c Fail the sbuf if vsnprintf(3) fails. 2015-10-02 09:23:14 +00:00
subr_scanf.c
subr_sfbuf.c Move KASSERT into locked region. 2014-08-11 15:06:07 +00:00
subr_sglist.c Fix a couple of panics when detaching from a cxgbe/cxl interface that was 2015-01-26 16:26:28 +00:00
subr_sleepqueue.c Revert for r277213: 2015-01-22 11:12:42 +00:00
subr_smp.c Since r289279 bufinit() uses mp_ncpus, but some architectures set this 2015-11-08 14:26:50 +00:00
subr_stack.c Add support for a configurable output channel to witness(4). 2015-11-19 05:56:59 +00:00
subr_syscall.c Support an arbitrary number of arguments to DTrace syscall probes. 2015-12-17 00:00:27 +00:00
subr_taskqueue.c This fixes several places where callout_stops return is examined. The 2015-11-13 22:51:35 +00:00
subr_terminal.c vt(4): Adjust the cursor position after changing the window size 2014-11-01 17:05:15 +00:00
subr_trap.c racct: perform a lockless check for p_throttled 2015-07-13 22:52:11 +00:00
subr_turnstile.c ddb: finish converting boolean values. 2015-05-21 15:16:18 +00:00
subr_uio.c Add asynchronous command support to the pass(4) driver, and the new 2015-12-03 20:54:55 +00:00
subr_unit.c
subr_vmem.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
subr_witness.c The buffer passed to an sbuf drain callback is not necessarily 2015-11-23 18:45:35 +00:00
sys_capability.c Introduce kern_cap_rights_limit(). 2015-08-11 08:43:50 +00:00
sys_generic.c Cover a race between doselwakeup() and selfdfree(). If doselwakeup() 2015-07-09 09:22:21 +00:00
sys_pipe.c Make pipes in CloudABI work. 2015-07-29 17:18:27 +00:00
sys_procdesc.c The si_status field of the siginfo_t, provided by the waitid(2) and 2015-07-18 09:02:50 +00:00
sys_process.c Add ptrace(2) reporting for LWP events. 2015-12-29 23:25:26 +00:00
sys_socket.c In preparation of merging projects/sendfile, transform bare access to 2014-11-12 09:57:15 +00:00
syscalls.c Missing regen after last change to sys/kern/syscalls.master. 2015-10-22 21:30:39 +00:00
syscalls.master Regenerate syscalls. 2015-07-11 15:22:11 +00:00
systrace_args.c Regenerate syscalls. 2015-07-11 15:22:11 +00:00
sysv_ipc.c
sysv_msg.c Add kern.racct.enable tunable and RACCT_DISABLED config option. 2015-04-29 10:23:02 +00:00
sysv_sem.c Add kern.racct.enable tunable and RACCT_DISABLED config option. 2015-04-29 10:23:02 +00:00
sysv_shm.c Change the default setting of kern.ipc.shm_allow_removed from 0 to 1. 2015-10-10 09:29:47 +00:00
tty_compat.c
tty_info.c
tty_inq.c
tty_outq.c
tty_pts.c Implement lockless resource limits. 2015-06-10 10:48:12 +00:00
tty_tty.c tty: replace several curthread->td_proc with stored curproc 2015-07-06 18:53:56 +00:00
tty_ttydisc.c Don't clear the software flow control flag before draining for last 2016-01-26 14:46:39 +00:00
tty.c Don't clear the software flow control flag before draining for last 2016-01-26 14:46:39 +00:00
uipc_accf.c The accept filter code is not specific to the FreeBSD IPv4 network stack, 2014-07-26 19:27:34 +00:00
uipc_debug.c Fix sb_state constant names as used e.g. to display in DDB ``show sockbuf''. 2015-07-21 09:57:13 +00:00
uipc_domain.c CALLOUT_MPSAFE has lost its meaning since r141428, i.e., for more than ten 2015-05-22 17:05:21 +00:00
uipc_mbuf2.c Add const-qualifiers for source mbuf argument in m_dup(), m_copym(), 2015-08-08 15:50:46 +00:00
uipc_mbuf.c New sendfile(2) syscall. A joint effort of NGINX and Netflix from 2013 and 2016-01-08 20:34:57 +00:00
uipc_mbufhash.c Reduce header pollution. 2015-03-17 14:16:50 +00:00
uipc_mqueue.c fd: remove filedesc argument from fdclose 2015-04-11 15:40:28 +00:00
uipc_sem.c Call ksem_get() with initialized 'rights'. 2015-07-23 23:18:03 +00:00
uipc_shm.c A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). 2015-12-16 21:30:45 +00:00
uipc_sockbuf.c Make it possible for sbappend() to preserve M_NOTREADY on mbufs, just like 2016-01-08 19:03:20 +00:00
uipc_socket.c Make shutdown() return ENOTCONN as required by POSIX, part deux. 2015-07-27 13:17:57 +00:00
uipc_syscalls.c - Separate sendfile(2) implementation from uipc_syscalls.c into 2016-01-22 02:23:18 +00:00
uipc_usrreq.c Make it possible for sbappend() to preserve M_NOTREADY on mbufs, just like 2016-01-08 19:03:20 +00:00
vfs_acl.c Replace struct filedesc argument in getvnode with struct thread 2015-06-16 13:09:18 +00:00
vfs_aio.c AIO daemons have always been kernel processes to facilitate switching to 2016-01-21 02:20:38 +00:00
vfs_bio.c Don't call wakeup if we're just returning reserved space; just 2015-12-16 00:13:16 +00:00
vfs_cache.c cache: minor changes 2016-01-21 01:09:39 +00:00
vfs_cluster.c Refactor unmapped buffer address handling. 2015-07-23 19:13:41 +00:00
vfs_default.c Two fixes for excessive iterations after r292326. 2016-01-05 14:48:40 +00:00
vfs_export.c MFP r287070,r287073: split radix implementation and route table structure. 2016-01-25 06:33:15 +00:00
vfs_extattr.c Replace struct filedesc argument in getvnode with struct thread 2015-06-16 13:09:18 +00:00
vfs_hash.c Track changes to kern.maxvnodes and appropriately increase or decrease 2015-09-06 05:50:51 +00:00
vfs_init.c sysctl: switch sysctllock to a sleepable rmlock, take 2 2015-09-15 23:06:56 +00:00
vfs_lookup.c save some bytes by using more concise SDT_PROBE<n> instead of SDT_PROBE 2015-09-28 12:14:16 +00:00
vfs_mount.c Make vfs_unmountall() unmount /dev after /, not before. The only 2015-08-24 13:18:13 +00:00
vfs_mountroot.c After r290196, the kernel won't wait for stuff like gmirror nodes 2015-10-30 15:52:10 +00:00
vfs_subr.c Add vrefl(), a locked variant of vref(9). 2016-01-18 22:21:46 +00:00
vfs_syscalls.c The freebsd4_getfsstat() was broken in r281551 to always return 0 on success. 2015-11-20 14:08:12 +00:00
vfs_vnops.c The struct file f_advice member is overlaid with the devfs f_cdevpriv 2016-01-22 20:35:20 +00:00
vnode_if.src A change to KPI of vm_pager_get_pages() and underlying VOP_GETPAGES(). 2015-12-16 21:30:45 +00:00