In the current code, the locking is completely broken and may lead
easilly to deadlocks. Fix it by using the proc_mtx, linked to the
suspending thread, as lock for the operation. Keep using the
thread_lock for setting and reading the flag even if it is not entirely
necessary (atomic ops may do it as well, but this way the code is more
readable).
- Fix a deadlock within kthread_suspend().
The suspender should not sleep on a different channel wrt the suspended
thread, or, otherwise, the awaker should wakeup both. Uniform the
interface to what the kproc_* counterparts do (sleeping on the same
channel).
- Change the kthread_suspend_check() prototype.
kthread_suspend_check() always assumes curthread and must only refer to
it, so skip the thread pointer as it may be easilly mistaken.
If curthread is not a kthread, the system will panic.
In collabouration with: jhb
Tested by: Giovanni Trematerra
<giovanni dot trematerra at gmail dot com>
MFC: 2 weeks
Some Exchange systems wrap lines over 75 characters long while converting
messages to quoted-printable, preventing ctm_rmail from reassembling
emailed deltas. For a negligible loss of encoding efficiency, this change
allows ctm deltas to once more pass through Exchange undamaged.
available for use. All data below this address considered to be used
by kernel. Along with kernel own data it might be symbol tables
prepeared by trampoline code, boot loader service data passed for
further analysis by kernel, etc... By default kernel_kseg0_end points
to the end of loaded kernel.
- Introduce mips_postboot_fixup function. It checks for symbol information
copied by ELF trampoline and passes it to KDB
so on architectures with strict alignment requirements we can't just simply
cast the latter to the former but need to copy it bytewise instead.
PR: 143010
MFC after: 3 days
For PT_TO_SCE stop that stops the ptraced process upon syscall entry,
syscall arguments are collected before ptracestop() is called. As a
consequence, debugger cannot modify syscall or its arguments.
In syscall(), reread syscall number and arguments after ptracestop(),
if debugger modified anything in the process environment. Since procfs
stopevent requires number of syscall arguments in p_xstat, this cannot
be solved by moving stop/trace point before argument fetching.
Move the code to read arguments into separate function
fetch_syscall_args() to avoid code duplication. Note that ktrace point
for modified syscall is intentionally recorded twice, once with original
arguments, and second time with the arguments set by debugger.
PT_TO_SCX stop is executed after cpu_syscall_set_retval() already.
Reviewed by: kib
frontend uses the same uPD7210 backend as the pcii ISA frontend, so
the backend has to cope with both situations.
Also, hide the first printf in pcii_probe (address mismatch) behind
bootverbose as the ISA bus parent tries to probe all configured ISA
devices against each driver, so a the console has been cluttered with
this message for a bunch of unrelated driver probes.
MFC after: 3 days
In the case of the thread being on a sleepqueue or a turnstile, the
sched_lock was acquired (without the aid of the td_lock interface) and
the td_lock was dropped. This was going to break locking rules on other
threads willing to access to the thread (via the td_lock interface) and
modify his flags (allowed as long as the container lock was different
by the one used in sched_switch).
In order to prevent this situation, while sched_lock is acquired there
the td_lock gets blocked. [0]
- Merge the ULE's internal function thread_block_switch() into the global
thread_lock_block() and make the former semantic as the default for
thread_lock_block(). This means that thread_lock_block() will not
disable interrupts when called (and consequently thread_unlock_block()
will not re-enabled them when called). This should be done manually
when necessary.
Note, however, that ULE's thread_unblock_switch() is not reaped
because it does reflect a difference in semantic due in ULE (the
td_lock may not be necessarilly still blocked_lock when calling this).
While asymmetric, it does describe a remarkable difference in semantic
that is good to keep in mind.
[0] Reported by: Kohji Okuno
<okuno dot kohji at jp dot panasonic dot com>
Tested by: Giovanni Trematerra
<giovanni dot trematerra at gmail dot com>
MFC: 2 weeks
syscall arguments are collected before ptracestop() is called. As a
consequence, debugger cannot modify syscall or its arguments.
For i386, amd64 and ia32 on amd64 MD syscall(), reread syscall number
and arguments after ptracestop(), if debugger modified anything in the
process environment. Since procfs stopeven requires number of syscall
arguments in p_xstat, this cannot be solved by moving stop/trace point
before argument fetching.
Move the code to read arguments into separate function
fetch_syscall_args() to avoid code duplication. Note that ktrace point
for modified syscall is intentionally recorded twice, once with original
arguments, and second time with the arguments set by debugger.
PT_TO_SCX stop is executed after cpu_syscall_set_retval() already.
Reported by: Ali Polatel <alip exherbo org>
Briefly discussed with: jhb
MFC after: 3 weeks
I've noticed many applications do a bad job at timekeeping, for several
reasons:
- Applications like screen(1) don't update time records when restoring
the old user login record.
- Many applications only set ut_tv.tv_sec, not ut_tv.tv_usec.
This causes many problems for tools such as ac(8), which require the
timestamps to be properly ordered. This is why I've decided to let the
utmpx code obtain valid timestamps itself.
Instead of trying to reference-count them and free them as soon
as they are no longer needed, we now just keep them around and free
them all when we release the archive object. This fixes a number
of minor memory leaks, especially when reading damaged archives.
. Properly allocate all IO space resources. These cards scatter their
IO addresses over a range of 0x1600 bytes, and they require an
additional address for "special interrupt handling".
. Implement the "special interrupt handling" per the GPIB-PCIIA
Technical Reference Manual; this was apparently not declared for the
clone card this driver has been originally implemented for, but it
turned out to be needed for both, an original NI brand PCII/PCIIA
card as well as the Axiom AX5488 clone.
. Add some diagnostic messages for various resource allocation etc.
failures during probe.
. Add some comments about the structure of the IO address space that
is used by these cards.
MFC after: 1 day
kept for compatibility with 4.4BSD behavior.
- Sync SYNOPSIS with usage().
- Use an alternative way to represent short and long options which have
same semantics.
Reviewed by: gabor
