Deadlock condition:
The return value of TDQ_LOCKPTR(td) is the same for two threads.
1) The first thread signals a wakeup while keeping the rcu_read_lock().
This invokes sched_add() which in turn will try to lock TDQ_LOCK().
2) The second thread is calling synchronize_rcu() calling mi_switch() over
and over again trying to yield(). This prevents the first thread from running
and releasing the RCU reader lock.
Solution:
Release the thread lock while yielding to allow other threads to acquire the
lock pointed to by TDQ_LOCKPTR(td).
Found by: KrishnamRaju ErapaRaju <Krishna2@chelsio.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies
Drop the EARLY_AP_STARTUP gtaskqueue code, as gtaskqueues are now
initialized before APs are started.
Reviewed by: hselasky@, jhb@
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D12054
in the VM area structure in the LinuxKPI when doing mmap() and that
unsupported bits are masked away.
While at it fix some redundant use of parenthesing inside some related
macros.
Found by: KrishnamRaju ErapaRaju <Krishna2@chelsio.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies
Such drivers attach to a vgapci bus rather than directly to a pci bus. For
the rest of the LinuxKPI to work correctly in this case, we override the
vgapci bus' ivars with those of the grandparent.
Reviewed by: hselasky
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11932
after r319757.
1) Correct the return value from __wait_event_common() from 1 to 0 in
case the timeout is specified as MAX_SCHEDULE_TIMEOUT. In the other
case __ret is zero and will be substituted in the last part of the
macro with the appropriate value before return.
2) Make sure the "timeout" argument is casted to "int" before
evaluating negativity. Else the signedness of a "long" might be
checked instead of the signedness of an integer.
3) The wait_event() function should not have a return value.
Found by: KrishnamRaju ErapaRaju <Krishna2@chelsio.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies
handles a timeout value of MAX_SCHEDULE_TIMEOUT which basically means there
is no timeout. This is a regression issue after r319757.
While at it change the type of returned variable from "long" to "int" to
match the actual return type.
MFC after: 1 week
Sponsored by: Mellanox Technologies
LinuxKPI workqueue wrappers reported "successful" cancellation for works
already completed in normal way. This change brings reported status and
real cancellation fact into sync. This required for drm-next operation.
Reviewed by: hselasky (earlier version)
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D11904
While there, switch to FreeBSD internal callout active status.
Reviewed by: markj, hselasky
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D11900
o Replace __riscv64 with (__riscv && __riscv_xlen == 64)
This is required to support new GCC 7.1 compiler.
This is compatible with current GCC 6.1 compiler.
RISC-V is extensible ISA and the idea here is to have built-in define
per each extension, so together with __riscv we will have some subset
of these as well (depending on -march string passed to compiler):
__riscv_compressed
__riscv_atomic
__riscv_mul
__riscv_div
__riscv_muldiv
__riscv_fdiv
__riscv_fsqrt
__riscv_float_abi_soft
__riscv_float_abi_single
__riscv_float_abi_double
__riscv_cmodel_medlow
__riscv_cmodel_medany
__riscv_cmodel_pic
__riscv_xlen
Reviewed by: ngie
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D11901
wide enough to hold the full 64-bit dev_t. Instead use the "dev" field in
the "linux_cdev" structure to store and lookup this value.
While at it remove superfluous use of parenthesis inside the
MAJOR(), MINOR() and MKDEV() macros in the LinuxKPI.
MFC after: 1 week
Sponsored by: Mellanox Technologies
Use them in some existing code that is vulnerable to roundoff errors.
The existing constant SBT_1NS is a honeypot, luring unsuspecting folks into
writing code such as long_timeout_ns*SBT_1NS to generate the argument for a
sleep call. The actual value of 1ns in sbt units is ~4.3, leading to a
large roundoff error giving a shorter sleep than expected when multiplying
by the trucated value of 4 in SBT_1NS. (The evil honeypot aspect becomes
clear after you waste a whole day figuring out why your sleeps return early.)
It looks like the __acquire and __release macros are for the consumption
of static analysis tools and have no semantic effect. Transform the
definitions from constant expressions to empty statements in order to
avoid -Wunused-value from gcc.
Likewise avoid future warnings for __chk_{user,io}_ptr, but with a cast
to void, because it looks like some linux kernel code may use those in
expression contexts.
Reviewed by: hselasky, markj
Approved by: markj (mentor)
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D11695
Also add some checks for overflow to existing functions.
Reviewed by: hselasky
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11533
Instead of mapping a dummy page upon a page fault, map the page
pointed to by the physical address given by IDX_TO_OFF(vmap->vm_pfn).
To simplify the implementation use OBJT_DEVICE to implement our own
linux_cdev_pager_fault() instead of using the existing
linux_cdev_pager_populate().
Some minor code factoring while at it.
Reviewed by: markj @
MFC after: 1 week
Sponsored by: Mellanox Technologies
Set "td_pinned" to zero after "sched_unbind()" to prevent "td_pinned"
from temporarily becoming negative during "sched_bind()". This can
happen if "sched_bind()" uses "sched_pin()" and "sched_unpin()".
MFC after: 1 week
Sponsored by: Mellanox Technologies
Add io_mapping_init_wc() and add a third (unused) parameter to
io_mapping_map_wc().
Reviewed by: hselasky
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D11286
memory map request. When the VM fault handler is NULL a return code of
VM_PAGER_BAD is returned from the character device's pager populate
handler. This fixes compatibility with Linux.
MFC after: 1 week
Sponsored by: Mellanox Technologies
