amd64 and i386.
The fillkpt loop is equivalent to the following:
do {
/* fill in the slot */
/* increment %ebx to the next slot */
/* increment %eax to the next pa */
} while (%ecx > 0)
The issue here is that if %ecx = 0 (i.e., the chunk we are trying to
map is zero-sized), there is still one entry created in the page table.
The kernel expects the va<->pa translation to be linear in low memory.
If there is a zero-sized chunk, the dead entry creates a +4096 offset in
the virtual space, with two consecutive entries that point to the same
physical address. In other words, the mappings are not linear anymore,
which causes the kernel to die.
Before my recent changes, there were only two big chunks that were
mapped, and neither of these could be zero-sized. Now, with multiple,
fine-grained chunks, it is possible that the [SYMS]+[PRELOADED_MODULES]
chunk could be zero-sized.
[PRELOADED_MODULES] is almost never here, and [SYMS] is always here on
default kernels. Except for floppies, where the bootloader does not load
[SYMS].
Should fix PR 51148.
as documented in sysctl(7):
0 - ptrace does not affect mprotect
1 - (default) mprotect is disabled for processes that start executing from
the debugger (being traced)
2 - mprotect restrictions are relaxed for traced processes
c450c13615f7af0673230041da4216b3de5bc4d3.patch
This patch fixes 2 issues in AccessWidth/BitOffset support and adds
comments to justify the BitOffset/BitWidth style macro usages. Lv Zheng.
This patch introduces ACPI_IS_ALIGNED() macro. Lv Zheng.
The old register descriptors are translated in AcpiTbInitGenericAddress()
with AccessWidth being filled with 0. This breaks code in
AcpiHwGetAccessBitWidth() when the registers are 16-bit IO ports and their
BitWidth fields are filled with 16. The rapid fix is meant to make code
written for AcpiHwGetAccessBitWidth() regression safer before the issue is
correctly fixed from AcpiTbInitGenericAddress(). Reported by
John Baldwin <jhb@freebsd.org>, Fixed by Lv Zheng <lv.zheng@intel.com>,
Tested by Jung-uk Kim <jkim@freebsd.org>.
mprotect settings so that debuggers can write to the text segment of traced
processes so that they can insert breakpoints. Turned off by default.
Ok: chuq (for now)
compat32, which we deal with properly). It would be possible to get
those working too, but it is not worth the code complexity.
This makes binaries compiled with -mcmodel=medlow (and ancient binaries)
work again on sparc64, smoothing the upgrade path.
ok: christos
Reduce obfuscation of errno handling. There is only one purpose
non-local errno handling is needed for: Inside el_wgets(), several
functions call down indirectly to el_wgetc(), many of them via the
dispatch table. When el_wgetc() fails, it does properly report
failure, but then various cleanup is done which may clobber errno.
But when returning due to failure, el_wgets() wants to have errno
set to the reason of the original read failure, not to the reason
of some subsequent failure of some cleanup operation. So el_wgetc()
needs to save errno, and if it's non-zero, el_wgets() needs to
restore it on failure.
This core logic is currently obscured by the fact that el_errno
is set and inspected at some additional places where it isn't needed.
Besides, since el_wgetc() and and el_wgets() are both in read.c,
el_errno does not need to be in struct editline, it can and should
be local to read.c in struct el_read_t.
Let's look at what can be simplified.
1. keymacro_get() abuses el_errno instead of having a proper
error return code. Adding that error return code is easy
because node_trav() already detects the condition and an
adequate code is already defined. Returning it, testing
for it in read_getcmd(), and returning with error from there
removes the need to inspect el_errno from el_wgets() after
calling read_getcmd().
Note that resetting lastchar and cursor and clearing buffer[0]
is irrelevant. The code returns from el_wgets() right afterwards.
Outside el_wgets(), these variables are no longer relevant.
When el_wgets() is called the next time, it will call ch_reset()
anyway, resetting the two pointers. And as long as lastchar
points to the beginning of the buffer, the contents of the
buffer won't be used for anything.
2. read_getcmd() doesn't need to set el_errno again after el_wgetc()
failure since el_wgetc() already did so. While here, remove
the silly "if EOF or error" comments from the el_wgetc()
return value tests. It's a public interface documented in a
manual, so people working on the implementation can obviously
be expected to know how it works. It's a case of
count++; /* Increment count. */
3. In the two code paths of el_wgets() that lead up to "goto noedit",
there is no need to save the errno because nothing that might
change it happens before returning.
For clarity, since el_wgets() is the function restoring the errno,
also move initializing it to the same function.
Finally, note that restoring errno when the saved value is zero is
wrong. No library code is ever allowed to clear a previously set
value of errno. Only application programs are allowed to do that,
and even they usually don't need to do so, except when using certain
ill-designed interfaces like strtol(3).
I tested that the behaviour remains sane in the following cases,
all during execution of el_wgets(3) and with a signal handler
for USR1 installed without SA_RESTART.
* Enter some text and maybe move around a bit.
Then send a USR1 signal.
The signal gets processed, then read_char() resumes reading.
Send another USR1 signal.
Now el_wgets() sets errno=EINTR and returns -1.
* Press Ctrl-V to activate ed-quoted-insert.
Then send a USR1 signal.
The signal gets processed, then read_char() resumes reading.
Send another USR1 signal.
ed_quoted_insert() returns ed_end_of_file(), i.e. CC_EOF,
and el_wgets() returns 0.
* Press a key starting a keyboard macro.
Then send a USR1 signal.
The signal gets processed, then read_char() resumes reading.
Send another USR1 signal.
Now el_wgets() sets errno=EINTR and returns -1.
* Press : to enter builtin command mode.
Start typing a command.
Then send a USR1 signal.
The signal gets processed, then read_char() resumes reading.
Send another USR1 signal.
Now c_gets() returns -1, ed_command() beeps and returns CC_REFRESH,
and el_wgets() resumes operation as it should.
I also tested with "el_set(el, EL_EDITMODE, 0)", and it returns
the right value and sets errno correctly.
sockets sitting in the accept filter can consume the entire listen queue,
such that the application is never able to handle any connections. Handle
this by simply passing through the oldest queued cxn when the queue is full.
This is fair because the longer a cxn lingers in the queue (stays connected
but does not meet the requirements of the filter for passage) the more likely
it is to be passed through, at which point the application can dispose of it.
Works because none of our accept filters actually allocate private state
per-cxn. If they did, we'd have to fix the API bug that there is presently
no way to tell an accf to finish/deallocate for a single cxn (accf_destroy
kills off the entire filter instance for a given listen socket).
