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PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign ->set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Add a pseudo RTC that simply is able to send an alarm signal
waking up the system at a given time in the future.
Since apparently timerfd_create() FDs don't support SIGIO, we
use the sigio-creating helper thread, which just learned to do
suspend/resume properly in the previous patch.
For time-travel mode, OTOH, just add an event at the specified
time in the future, and that's already sufficient to wake up
the system at that point in time since suspend will just be in
an "endless wait".
For s2idle support also call pm_system_wakeup().
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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This mostly reverts the old commit 3963333fe676 ("uml: cover stubs
with a VMA") which had added a VMA to the existing PTEs. However,
there's no real reason to have the PTEs in the first place and the
VMA cannot be 'fixed' in place, which leads to bugs that userspace
could try to unmap them and be forcefully killed, or such. Also,
there's a bit of an ugly hole in userspace's address space.
Simplify all this: just install the stub code/page at the top of
the (inner) address space, i.e. put it just above TASK_SIZE. The
pages are simply hard-coded to be mapped in the userspace process
we use to implement an mm context, and they're out of reach of the
inner mmap/munmap/mprotect etc. since they're above TASK_SIZE.
Getting rid of the VMA also makes vma_merge() no longer hit one of
the VM_WARN_ON()s there because we installed a VMA while the code
assumes the stack VMA is the first one.
It also removes a lockdep warning about mmap_sem usage since we no
longer have uml_setup_stubs() and thus no longer need to do any
manipulation that would require mmap_sem in activate_mm().
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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The userspace stacks mostly have a stack (and in the case of the
syscall stub we can just set their stack pointer) that points to
the location of the stub data page already.
Rework the stubs to use the stack pointer to derive the start of
the data page, rather than requiring it to be hard-coded.
In the clone stub, also integrate the int3 into the stack remap,
since we really must not use the stack while we remap it.
This prepares for putting the stub at a variable location that's
not part of the normal address space of the userspace processes
running inside the UML machine.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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If the two are mixed up, then it looks as though the parent
returned an error if the child failed (before) the mmap(),
and then the resulting process never gets killed. Fix this
by splitting the child and parent errors, reporting and
using them appropriately.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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In some cases we can get to fix_range_common() with mmap_sem held,
and in others we get there without it being held. For example, we
get there with it held from sys_mprotect(), and without it held
from fork_handler().
Avoid any issues in this and simply defer killing the task until
it runs the next time. Do it on the mm so that another task that
shares the same mm can't continue running afterwards.
Cc: stable@vger.kernel.org
Fixes: 468f65976a8d ("um: Fix hung task in fix_range_common()")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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If userspace tries to change the stub, we need to kill it,
because otherwise it can escape the virtual machine. In a
few cases the stub checks weren't good, e.g. if userspace
just tries to
mmap(0x100000 - 0x1000, 0x3000, ...)
it could succeed to get a new private/anonymous mapping
replacing the stubs. Fix this by checking everywhere, and
checking for _overlap_, not just direct changes.
Cc: stable@vger.kernel.org
Fixes: 3963333fe676 ("uml: cover stubs with a VMA")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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In external time-travel mode, where time is controlled via the
controller application socket, interrupt handling is a little
tricky. For example on virtio, the following happens:
* we receive a message (that requires an ACK) on the vhost-user socket
* we add a time-travel event to handle the interrupt
(this causes communication on the time socket)
* we ACK the original vhost-user message
* we then handle the interrupt once the event is triggered
This protocol ensures that the sender of the interrupt only continues
to run in the simulation when the time-travel event has been added.
So far, this was only done in the virtio driver, but it was actually
wrong, because only virtqueue interrupts were handled this way, and
config change interrupts were handled immediately. Additionally, the
messages were actually handled in the real Linux interrupt handler,
but Linux interrupt handlers are part of the simulation and shouldn't
run while there's no time event.
To really do this properly and only handle all kinds of interrupts in
the time-travel event when we are scheduled to run in the simulation,
rework this to plug in to the lower interrupt layers in UML directly:
Add a um_request_irq_tt() function that let's a time-travel aware
driver request an interrupt with an additional timetravel_handler()
that is called outside of the context of the simulation, to handle
the message only. It then adds an event to the time-travel calendar
if necessary, and no "real" Linux code runs outside of the time
simulation.
This also hooks in with suspend/resume properly now, since this new
timetravel_handler() can run while Linux is suspended and interrupts
are disabled, and decide to wake up (or not) the system based on the
message it received. Importantly in this case, it ACKs the message
before the system even resumes and interrupts are re-enabled, thus
allowing the simulation to progress properly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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In time-travel mode, since my previous patch, the start time was
initialized too late, so that the system would read it before we
set it, thus always starting system time at 0 (1970-01-01). This
happens because timekeeping_init() reads the time and is called
before time_init().
Unfortunately, I didn't see this before because I was testing it
only with the RTC patch applied (and enabled), and then the time
is read again by the RTC a little - after time_init() this time.
Fix this by just doing the initialization whenever necessary.
Fixes: 2701c1bd91dd ("um: time: Fix read_persistent_clock64() in time-travel")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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This reverts commit 963285b0b47a ("um: support some of
ARCH_HAS_SET_MEMORY"), as it turns out that it's not only not
working (due to um never using the protection bits in the
page tables) but also corrupts the page tables if used on a
non-vmalloc page, since um never allocates proper page tables
for the 'physmem' in the first place.
Fixing all this will take more effort, so for now revert it.
Reported-by: Benjamin Berg <benjamin@sipsolutions.net>
Fixes: 963285b0b47a ("um: support some of ARCH_HAS_SET_MEMORY")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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This reverts commit ef4459a6da09 ("um: allocate a guard page to
helper threads"), it's broken in multiple ways:
1) the free no longer matches the alloc; and
2) more importantly, the set_memory_ro() causes allocation of
page tables for the normal memory that doesn't have any,
and that later causes corruption and crashes (usually but
not always in vfree()).
We could fix the first bug and use vmalloc() to work around the
second, but set_memory_ro() actually doesn't do anything either
so I'll just revert that as well.
Reported-by: Benjamin Berg <benjamin@sipsolutions.net>
Fixes: ef4459a6da09 ("um: allocate a guard page to helper threads")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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With the addition of the ttynull console driver, the chance that a
console driver was already registerd did increase. Refine the logic when
to dump the kernel message buffer: always dump the buffer, when the UML
stdio console driver is not active and the preferred console.
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
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The addition of the "ttynull" console driver did break the ordering of the
UML stdio console driver.
The UML stdio console driver is added in late_initcall (7), whereby the
ttynull driver is added in device_initcall (6), which always does make the
ttynull driver the default console.
Fix it by explicitly adding the UML stdio console as the preferred console,
in case no 'console=' command line option was specified.
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
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uml_pm_wake() is unconditionally called from the SIGUSR1 wakeup
handler since that's in the userspace portion of UML, and thus
a bit tricky to ifdef out. Since pm_system_wakeup() can always
be called (but may be an empty inline), also simply always have
uml_pm_wake() to fix the build.
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Lockdep (on 5.10-rc) points out that we're delivering IRQs while IRQs
are not even enabled, which clearly shouldn't happen. Defer the time
event IRQ delivery until they actually are enabled.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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If the sigio workaround needed to be applied to a file descriptor,
set_irq_wake() wouldn't work for it since it would get polled by
the thread instead of causing SIGIO, and thus could never really
cause a wakeup, since the thread notification FD wasn't marked as
being able to wake up the system.
Fix this by marking the thread's notification FD explicitly as a
wake source FD, i.e. not suppressing SIGIO for it in suspend. In
order to not cause spurious wakeups, we then need to remove all
FDs that shouldn't wake up the system from the polling thread. In
order to do this, add unlocked versions of ignore_sigio_fd() and
add_sigio_fd() (nothing else is happening in suspend, so this is
fine), and also modify ignore_sigio_fd() to return -ENOENT if the
FD wasn't originally in there. This doesn't matter because nothing
else currently checks the return value, but the irq code needs to
know which ones to restore the workaround for.
All told, this lets us use a timerfd for the RTC clock in the next
patch, which doesn't send SIGIO.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Due a bug - we never checked the time_travel_ext_free_until value - we
were always requesting time for every single scheduling. This adds up
since we make reading time cost 256ns, and it's a fairly common call.
Fix this.
While at it, also make reading time only cost something when we're not
currently waiting for our scheduling turn - otherwise things get mixed
up in a very confusing way. We should never get here, since we're not
actually running, but it's possible if you stick printk() or such into
the virtio code that must handle the external interrupts.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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We've been running into stack overflows in helper threads
corrupting memory (e.g. because somebody put printf() or
os_info() there), so to avoid those causing hard-to-debug
issues later on, allocate a guard page for helper thread
stacks and mark it read-only.
Unfortunately, the crash dump at that point is useless as
the stack tracer will try to backtrace the *kernel* thread,
not the helper thread, but at least we don't survive to a
random issue caused by corruption.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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For now, only support set_memory_ro()/rw() which we need for
the stack protection in the next patch.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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If there is some kind of interrupt negotation or such then
it may happen that we send an update message multiple times,
avoid that in the interest of efficiency by storing the last
transmitted value and only sending a new update if it's not
the same as the last update.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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With all the previous bits in place, we can now also support
suspend to RAM, in the sense that everything is suspended,
not just most, including userspace, processes like in s2idle.
Since um_idle_sleep() now waits forever, we can simply call
that to "suspend" the system.
As before, you can wake it up using SIGUSR1 since we're just
in a pause() call that only needs to return.
In order to implement selective resume from certain devices,
and not have any arbitrary device interrupt wake up, suspend
interrupts by removing SIGIO notification (O_ASYNC) from all
the FDs that are not supposed to wake up the system. However,
swap out the handler so we don't actually handle the SIGIO as
an interrupt.
Since we're in pause(), the mere act of receiving SIGIO wakes
us up, and then after things have been restored enough, re-set
O_ASYNC for all previously suspended FDs, reinstall the proper
SIGIO handler, and send SIGIO to self to process anything that
might now be pending.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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In order to be able to experiment with suspend in UML, add the
minimal work to be able to suspend (s2idle) an instance of UML,
and be able to wake it back up from that state with the USR1
signal sent to the main UML process.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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In time-travel mode, we've relied on read_persistent_clock64()
being called only once at system startup, but this is both the
right thing to call from the pseudo-RTC, and also gets called
by the timekeeping core during suspend/resume.
Thus, fix this to always fall make use of the time_travel_time
in any time-travel mode, initializing time_travel_start at boot
to the right value depending on the time-travel mode.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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There really is no reason to pass the amount of time we should
sleep, especially since it's just hard-coded to one second.
Additionally, one second isn't really all that long, and as we
are expecting to be woken up by a signal, we can sleep longer
and avoid doing some work every second, so replace the current
clock_nanosleep() with just an empty select() that can _only_
be woken up by a signal.
We can also remove the deliver_alarm() since we don't need to
do that when we got e.g. SIGIO that woke us up, and if we got
SIGALRM the signal handler will actually (have) run, so it's
just unnecessary extra work.
Similarly, in time-travel mode, just program the wakeup event
from idle to be S64_MAX, which is basically the most you could
ever simulate to. Of course, you should already have an event
in the list that's earlier and will cause a wakeup, normally
that's the regular timer interrupt, though in suspend it may
(later) also be an RTC event. Since actually getting to this
point would be a bug and you can't ever get out again, panic()
on it in the time control code.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Reduce dynamic allocations (and thereby cache misses) by simply
embedding the registration data for IRQs in the irq_entry, we
never supported these being really dynamic anyway as only one
was ever allowed ("Trying to reregister ...").
Lockless behaviour is preserved by removing the FD from the poll
set appropriately, but we use reg->events to indicate whether or
not this entry is used, rather than dynamically allocating them.
Also port the list of IRQ entries to list_head instead of the
current open-coded singly-linked list implementation, just for
sanity.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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We don't actually use this in um_request_irq(), so it can
never be assigned. It's also not clear what that would be
useful for, so just remove it.
This results in quite a number of cleanups, all the way to
removing the "SIGIO on close" startup check, since the data
it assigns (pty_close_sigio) is not used anymore.
While at it, also make this an enum so we get a minimum of
type checking, and remove the IRQ_NONE hack in virtio since
we now no longer have the name twice.
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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We don't need an array of 4 entries to capture three and the
name 'MAX_IRQ_TYPE' really gets confusing as well. Remove it
and add a correct NUM_IRQ_TYPES, and use that correctly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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This really shouldn't be called "irq_fd" since it doesn't
carry an fd. Well, it used to, apparently, but that struct
member is unused.
Rename it to "irq_reg" since it more accurately reflects a
registered interrupt, and remove the unused 'next' and 'fd'
members from the struct as well.
While at it, also move it to the implementation, it's not
used anywhere else, and the header file is shared with the
userspace components.
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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We don't use "SIGVTALRM", it's just SIGALRM. Clean up the naming.
While at it, fix the comment's grammar.
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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It's cumbersome and error-prone to keep adding fixed IRQ numbers,
and for proper device wakeup support for the virtio/vhost-user
support we need to have different IRQs for each device. Even if
in theory two IRQs (with and without wake) might be sufficient,
it's much easier to reason about it when we have dynamic number
assignment. It also makes it easier to add new devices that may
dynamically exist or depending on the configuration, etc.
Add support for this, up to 64 IRQs (the same limit as epoll FDs
we have right now). Since it's not easy to port all the existing
places to dynamic allocation (some data is statically initialized)
keep the low numbers are reserved for the existing hard-coded IRQ
numbers.
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Since the time-travel rework, basic time-travel mode hasn't worked
properly, but there's no longer a need for this WARN_ON() so just
remove it and thereby fix things.
Cc: stable@vger.kernel.org
Fixes: 4b786e24ca80 ("um: time-travel: Rewrite as an event scheduler")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Wire up TIF_NOTIFY_SIGNAL handling for um.
Cc: linux-um@lists.infradead.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.
Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.
(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
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A couple of um files ended up not including the header file that defines
the __section() macro, and the simplest fix is to just revert the change
for those files.
Fixes: 33def8498fdd treewide: Convert macro and uses of __section(foo) to __section("foo")
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.
Remove the quote operator # from compiler_attributes.h __section macro.
Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.
Conversion done using the script at:
https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull arch task_work cleanups from Jens Axboe:
"Two cleanups that don't fit other categories:
- Finally get the task_work_add() cleanup done properly, so we don't
have random 0/1/false/true/TWA_SIGNAL confusing use cases. Updates
all callers, and also fixes up the documentation for
task_work_add().
- While working on some TIF related changes for 5.11, this
TIF_NOTIFY_RESUME cleanup fell out of that. Remove some arch
duplication for how that is handled"
* tag 'arch-cleanup-2020-10-22' of git://git.kernel.dk/linux-block:
task_work: cleanup notification modes
tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume()
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git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml
Pull UML updates from Richard Weinberger:
- Improve support for non-glibc systems
- Vector: Add support for scripting and dynamic tap devices
- Various fixes for the vector networking driver
- Various fixes for time travel mode
* tag 'for-linus-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: vector: Add dynamic tap interfaces and scripting
um: Clean up stacktrace dump
um: Fix incorrect assumptions about max pid length
um: Remove dead usage of TIF_IA32
um: Remove redundant NULL check
um: change sigio_spinlock to a mutex
um: time-travel: Return the sequence number in ACK messages
um: time-travel: Fix IRQ handling in time_travel_handle_message()
um: Allow static linking for non-glibc implementations
um: Some fixes to build UML with musl
um: vector: Use GFP_ATOMIC under spin lock
um: Fix null pointer dereference in vector_user_bpf
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All the callers currently do this, clean it up and move the clearing
into tracehook_notify_resume() instead.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull orphan section checking from Ingo Molnar:
"Orphan link sections were a long-standing source of obscure bugs,
because the heuristics that various linkers & compilers use to handle
them (include these bits into the output image vs discarding them
silently) are both highly idiosyncratic and also version dependent.
Instead of this historically problematic mess, this tree by Kees Cook
(et al) adds build time asserts and build time warnings if there's any
orphan section in the kernel or if a section is not sized as expected.
And because we relied on so many silent assumptions in this area, fix
a metric ton of dependencies and some outright bugs related to this,
before we can finally enable the checks on the x86, ARM and ARM64
platforms"
* tag 'core-build-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
x86/boot/compressed: Warn on orphan section placement
x86/build: Warn on orphan section placement
arm/boot: Warn on orphan section placement
arm/build: Warn on orphan section placement
arm64/build: Warn on orphan section placement
x86/boot/compressed: Add missing debugging sections to output
x86/boot/compressed: Remove, discard, or assert for unwanted sections
x86/boot/compressed: Reorganize zero-size section asserts
x86/build: Add asserts for unwanted sections
x86/build: Enforce an empty .got.plt section
x86/asm: Avoid generating unused kprobe sections
arm/boot: Handle all sections explicitly
arm/build: Assert for unwanted sections
arm/build: Add missing sections
arm/build: Explicitly keep .ARM.attributes sections
arm/build: Refactor linker script headers
arm64/build: Assert for unwanted sections
arm64/build: Add missing DWARF sections
arm64/build: Use common DISCARDS in linker script
arm64/build: Remove .eh_frame* sections due to unwind tables
...
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We currently get a few stray newlines, due to the interaction
between printk() and the code here. Remove a few explicit
newline prints to neaten the output.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Lockdep complains at boot:
=============================
[ BUG: Invalid wait context ]
5.7.0-05093-g46d91ecd597b #98 Not tainted
-----------------------------
swapper/1 is trying to lock:
0000000060931b98 (&desc[i].request_mutex){+.+.}-{3:3}, at: __setup_irq+0x11d/0x623
other info that might help us debug this:
context-{4:4}
1 lock held by swapper/1:
#0: 000000006074fed8 (sigio_spinlock){+.+.}-{2:2}, at: sigio_lock+0x1a/0x1c
stack backtrace:
CPU: 0 PID: 1 Comm: swapper Not tainted 5.7.0-05093-g46d91ecd597b #98
Stack:
7fa4fab0 6028dfd1 0000002a 6008bea5
7fa50700 7fa50040 7fa4fac0 6028e016
7fa4fb50 6007f6da 60959c18 00000000
Call Trace:
[<60023a0e>] show_stack+0x13b/0x155
[<6028e016>] dump_stack+0x2a/0x2c
[<6007f6da>] __lock_acquire+0x515/0x15f2
[<6007eb50>] lock_acquire+0x245/0x273
[<6050d9f1>] __mutex_lock+0xbd/0x325
[<6050dc76>] mutex_lock_nested+0x1d/0x1f
[<6008e27e>] __setup_irq+0x11d/0x623
[<6008e8ed>] request_threaded_irq+0x169/0x1a6
[<60021eb0>] um_request_irq+0x1ee/0x24b
[<600234ee>] write_sigio_irq+0x3b/0x76
[<600383ca>] sigio_broken+0x146/0x2e4
[<60020bd8>] do_one_initcall+0xde/0x281
Because we hold sigio_spinlock and then get into requesting
an interrupt with a mutex.
Change the spinlock to a mutex to avoid that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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For external time travel, the protocol says to return the
incoming sequence number in the ACK message to aid debugging,
so do that.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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As the comment here indicates, we need to do the polling in the
idle loop without blocking interrupts, since interrupts can be
vhost-user messages that we must process even while in our idle
loop.
I don't know why I explained one thing and implemented another,
but we have indeed observed random hangs due to this, depending
on the timing of the messages.
Fixes: 88ce64249233 ("um: Implement time-travel=ext")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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The .comment section doesn't belong in STABS_DEBUG. Split it out into a
new macro named ELF_DETAILS. This will gain other non-debug sections
that need to be accounted for when linking with --orphan-handling=warn.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: linux-arch@vger.kernel.org
Link: https://lore.kernel.org/r/20200821194310.3089815-5-keescook@chromium.org
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Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.
[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
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Here're the last pieces of page fault accounting that were still done
outside handle_mm_fault() where we still have regs==NULL when calling
handle_mm_fault():
arch/powerpc/mm/copro_fault.c: copro_handle_mm_fault
arch/sparc/mm/fault_32.c: force_user_fault
arch/um/kernel/trap.c: handle_page_fault
mm/gup.c: faultin_page
fixup_user_fault
mm/hmm.c: hmm_vma_fault
mm/ksm.c: break_ksm
Some of them has the issue of duplicated accounting for page fault
retries. Some of them didn't do the accounting at all.
This patch cleans all these up by letting handle_mm_fault() to do per-task
page fault accounting even if regs==NULL (though we'll still skip the perf
event accountings). With that, we can safely remove all the outliers now.
There's another functional change in that now we account the page faults
to the caller of gup, rather than the task_struct that passed into the gup
code. More information of this can be found at [1].
After this patch, below things should never be touched again outside
handle_mm_fault():
- task_struct.[maj|min]_flt
- PERF_COUNT_SW_PAGE_FAULTS_[MAJ|MIN]
[1] https://lore.kernel.org/lkml/CAHk-=wj_V2Tps2QrMn20_W0OJF9xqNh52XSGA42s-ZJ8Y+GyKw@mail.gmail.com/
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200707225021.200906-25-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patch series "mm: Page fault accounting cleanups", v5.
This is v5 of the pf accounting cleanup series. It originates from Gerald
Schaefer's report on an issue a week ago regarding to incorrect page fault
accountings for retried page fault after commit 4064b9827063 ("mm: allow
VM_FAULT_RETRY for multiple times"):
https://lore.kernel.org/lkml/20200610174811.44b94525@thinkpad/
What this series did:
- Correct page fault accounting: we do accounting for a page fault
(no matter whether it's from #PF handling, or gup, or anything else)
only with the one that completed the fault. For example, page fault
retries should not be counted in page fault counters. Same to the
perf events.
- Unify definition of PERF_COUNT_SW_PAGE_FAULTS: currently this perf
event is used in an adhoc way across different archs.
Case (1): for many archs it's done at the entry of a page fault
handler, so that it will also cover e.g. errornous faults.
Case (2): for some other archs, it is only accounted when the page
fault is resolved successfully.
Case (3): there're still quite some archs that have not enabled
this perf event.
Since this series will touch merely all the archs, we unify this
perf event to always follow case (1), which is the one that makes most
sense. And since we moved the accounting into handle_mm_fault, the
other two MAJ/MIN perf events are well taken care of naturally.
- Unify definition of "major faults": the definition of "major
fault" is slightly changed when used in accounting (not
VM_FAULT_MAJOR). More information in patch 1.
- Always account the page fault onto the one that triggered the page
fault. This does not matter much for #PF handlings, but mostly for
gup. More information on this in patch 25.
Patchset layout:
Patch 1: Introduced the accounting in handle_mm_fault(), not enabled.
Patch 2-23: Enable the new accounting for arch #PF handlers one by one.
Patch 24: Enable the new accounting for the rest outliers (gup, iommu, etc.)
Patch 25: Cleanup GUP task_struct pointer since it's not needed any more
This patch (of 25):
This is a preparation patch to move page fault accountings into the
general code in handle_mm_fault(). This includes both the per task
flt_maj/flt_min counters, and the major/minor page fault perf events. To
do this, the pt_regs pointer is passed into handle_mm_fault().
PERF_COUNT_SW_PAGE_FAULTS should still be kept in per-arch page fault
handlers.
So far, all the pt_regs pointer that passed into handle_mm_fault() is
NULL, which means this patch should have no intented functional change.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200707225021.200906-1-peterx@redhat.com
Link: http://lkml.kernel.org/r/20200707225021.200906-2-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Most architectures define pgd_free() as a wrapper for free_page().
Provide a generic version in asm-generic/pgalloc.h and enable its use for
most architectures.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-7-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
For most architectures that support >2 levels of page tables,
pmd_alloc_one() is a wrapper for __get_free_pages(), sometimes with
__GFP_ZERO and sometimes followed by memset(0) instead.
More elaborate versions on arm64 and x86 account memory for the user page
tables and call to pgtable_pmd_page_ctor() as the part of PMD page
initialization.
Move the arm64 version to include/asm-generic/pgalloc.h and use the
generic version on several architectures.
The pgtable_pmd_page_ctor() is a NOP when ARCH_ENABLE_SPLIT_PMD_PTLOCK is
not enabled, so there is no functional change for most architectures
except of the addition of __GFP_ACCOUNT for allocation of user page
tables.
The pmd_free() is a wrapper for free_page() in all the cases, so no
functional change here.
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-5-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Now that HAVE_COPY_THREAD_TLS has been removed, rename copy_thread_tls()
back simply copy_thread(). It's a simpler name, and doesn't imply that only
tls is copied here. This finishes an outstanding chunk of internal process
creation work since we've added clone3().
Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>A
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>A
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
|
