Coredump notes depend on being able to invoke dump routines twice; once
in a dry-run mode to get the size of the note, and another to actually
emit the note to the corefile.
When a note helper emits a different length section the second time
around than the length it requested the first time, the kernel produces
a corrupt coredump.
NT_PROCSTAT_FILES output length, when packing kinfo structs, is tied to
the length of filenames corresponding to vnodes in the process' fd table
via vn_fullpath. As vnodes may move around during dump, this is racy.
So:
- Detect badly behaved notes in putnote() and pad underfilled notes.
- Add a fail point, debug.fail_point.fill_kinfo_vnode__random_path to
exercise the NT_PROCSTAT_FILES corruption. It simply picks random
lengths to expand or truncate paths to in fo_fill_kinfo_vnode().
- Add a sysctl, kern.coredump_pack_fileinfo, to allow users to
disable kinfo packing for PROCSTAT_FILES notes. This should avoid
both FILES note corruption and truncation, even if filenames change,
at the cost of about 1 kiB in padding bloat per open fd. Document
the new sysctl in core.5.
- Fix note_procstat_files to self-limit in the 2nd pass. Since
sometimes this will result in a short write, pad up to our advertised
size. This addresses note corruption, at the risk of sometimes
truncating the last several fd info entries.
- Fix NT_PROCSTAT_FILES consumers libutil and libprocstat to grok the
zero padding.
With suggestions from: bjk, jhb, kib, wblock
Approved by: markj (mentor)
Relnotes: yes
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3548
operations that map a single page that has an associated vm_page_t.
This does not permit mapping larger regions (such as a PCI memory
BAR) and it does not permit mapping addresses beyond the top of RAM
(such as a 64-bit BAR located above the top of RAM).
Instead of using a single OBJT_DEVICE object and passing the physaddr via
the offset as a hack, create a new sglist and OBJT_SG object for each
mmap request. The requested memory attribute is applied to the object
thus affecting all pages mapped by the request.
Reviewed by: hselasky, np
MFC after: 1 week
Sponsored by: Chelsio
Differential Revision: https://reviews.freebsd.org/D3386
delete a logic volume on status change which is NOT what we want here.
The original code is correct in that when the volume changes status
the driver will only delete the volume if the status is one of the
fatal errors. A drive failure in a mirrored volume is NOT a situtation
where the volume should dissapear.
Reported on freebsd-scsi@:
https://lists.freebsd.org/pipermail/freebsd-scsi/2015-September/006800.html
MFC after: 3 days
basics. The more complicated cases - like how to use physical
ports - are explained later, in the "EXAMPLES" section.
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
PCI BARs does not necessarily correspond to the upper-left
most pixel. Scan the frame buffer for which byte changed
when changing the pixel at (0,0).
Use the same technique to determine the stride. Except for
changing the pixel at (0,0), we change the pixel at (0,1).
PR: 202730
Tested by: hartzell (at) alerce.com
so they were disabled during DTS transition. Though there are
no standard devices/drivers on them people might use iic(4) userland
interface to access these buses.
Originally it was added in order to prevent trashing of objects with
INVARIANTS enabled. The same effect is now provided with mere UMA_ZONE_NOFREE.
This reverts r286921.
Discussed with: kib
Objects obtained from such zones are supposed to retain type stability,
which was violated by aforementioned trashing.
This is a follow-up to r284861.
Discussed with: kib
broke in two ways. One, the pacing variable was accessed in multiple
threads in an unsafe way. Two, since large numbers of I/O could come
down from the buf layer at one time, large numbers of allocation
failures could happen all at once, resulting in a huge pace value that
would limit I/Os to 10 IOPS for minutes (or even hours) at a
time. While a real solution to these problems requires substantial
work (to go to a no-allocation after the first model, or to have some
way to wait for more memory with some kind of reserve for pager and
swapper requests), it is relatively easy to make this simplistic
pacing less pathological.
Move to using a volatile variable with loads and stores. While this is
a little racy, losing the race is safe: either you get memory and
proceed, or you don't and queue. Second, sleep for 1ms (or one tick, whichever
is larger) instead of 100ms. This removes the artificial 10 IOPS limit
while still easing up on new I/Os during memory shortages. Remove
tying the amount of time we do this to the number of failed requests
and do it only as long as we keep failing requests.
Finally, to avoid needless recursion when memory is tight (start ->
g_io_deliver() -> g_io_request() -> start -> ... until we use 1/2 the
stack), don't do direct dispatch while pacing. This should be a rare
event (not steady state) so the performance hit here is worth the
extra safety of not starving g_down() with directly dispatched I/O.
Differential Review: https://reviews.freebsd.org/D3546
the buffer. (n == hostlen) also means the buffer length was
too short.
- Use sdl->sdl_data only when (sdl->sdl_nlen > 0 && sdl->sdl_alen == 0)
to prevent redundant output.
Resetting some generations of the I/OAT hardware (just BDXDE for now)
resets the corresponding MSI-X registers. So, teardown and
re-initialize interrupts after resetting the hardware.
Reviewed by: jimharris
Approved by: markj (mentor)
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D3549
a one word variable, which is quite unexpected from documentation.
So, to avoid double installation of a single kernel, protect the extra
kernels loop with ${BUILDKERNELS:[#]} > 1 conditional.
Sponsored by: Netflix
Sponsored by: Nginx, Inc.
go asking what debug flags to set for GEOM to make it work. Advice
them to use gpart(8) instead.
Something similar should probably done with disklabel,
but I need to rewrite the disklabel examples first.
Reviewed by: wblock@
MFC after: 1 month
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3315
o In pccard_ether add code to start children of a 802.11
device, that are configured in rc.conf.
o In devd.conf provide a regex matching all 802.11 devices,
and on match run pccard_ether to spawn children.
PR: 202784
Submitted by: <vidwer gmail.com>
In collaboration with: "Oleg V. Nauman" <oleg opentransfer.com>
and exit events. procfs stop events for system call tracing report these
values (argument count for system call entry and code for system call exit),
but ptrace() does not provide this information. (Note that while the system
call code can be determined in an ABI-specific manner during system call
entry, it is not generally available during system call exit.)
The values are exported via new fields at the end of struct ptrace_lwpinfo
available via PT_LWPINFO.
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D3536
