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The write_sigio thread is not really a traditional thread. Set
the parent-death signal for it to ensure that it will be killed
if the UML kernel dies unexpectedly without proper cleanup.
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20241024142828.2612828-4-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
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This reverts commit 9b0da3f22307af693be80f5d3a89dc4c7f360a85.
The sigio.c is clearly user space code which is handled by
arch/um/scripts/Makefile.rules (see USER_OBJS rule).
The above mentioned commit simply broke this agreement,
we may not use Linux kernel internal headers in them without
thorough thinking.
Hence, revert the wrong commit.
Link: https://lkml.kernel.org/r/20230724143131.30090-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202307212304.cH79zJp1-lkp@intel.com/
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Herve Codina <herve.codina@bootlin.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Richard Weinberger <richard@nod.at>
Cc: Yang Guang <yang.guang5@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Use the macro 'swap()' defined in 'include/linux/minmax.h' to avoid
opencoding it.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Yang Guang <yang.guang5@zte.com.cn>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Rename set_signals() as there's at least one driver that
uses the same name and can now be built on UM due to PCI
support, and thus we can get symbol conflicts.
Also rename set_signals_trace() to be consistent.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 68f5d3f3b654 ("um: add PCI over virtio emulation driver")
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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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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If we run out of space, return an error instead of 0.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Convert files to use SPDX header. All files are licensed under the GPLv2.
Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
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UML enables TRACE_IRQFLAGS_SUPPORT but doesn't actually implement
it. It seems to have been added for lockdep support, but that can't
actually really work well without IRQ flags tracing, as is also
very noisily reported when enabling CONFIG_DEBUG_LOCKDEP.
Implement it now.
Fixes: 711553efa5b8 ("[PATCH] uml: declare in Kconfig our partial LOCKDEP support")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Richard reported that some UML processes survive if the UML
main process receives a SIGTERM.
This issue was caused by a wrongly placed signal(SIGTERM, SIG_DFL)
in init_new_thread_signals().
It disabled the UML exit handler accidently for some processes.
The correct solution is to disable the fatal handler for all
UML helper threads/processes.
Such that last_ditch_exit() does not get called multiple times
and all processes can exit due to SIGTERM.
Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
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- Make some variables and functions static, since they don't need to be
global.
- Remove an unused function - arch/um/kernel/time.c::sched_clock().
- Clean the style a bit as complained by checkpatch.pl.
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The random driver would essentially hang if the host's /dev/random returned
-EAGAIN. There was a test of need_resched followed by a schedule inside the
loop, but that didn't help and it's the wrong way to work anyway.
The right way is to ask for an interrupt when there is input available from
the host and handle it then rather than polling.
Now, when the host's /dev/random returns -EAGAIN, the driver asks for a wakeup
when there's randomness available again and sleeps. The interrupt routine
just wakes up whatever processes are sleeping on host_read_wait.
There is an atomic_t, host_sleep_count, which counts the number of processes
waiting for randomness. When this reaches zero, the interrupt is disabled.
An added complication is that async I/O notification was only recently added
to /dev/random (by me), so essentially all hosts will lack it. So, we use the
sigio workaround here, which is to have a separate thread poll on the
descriptor and send an interrupt when there is input on it. This mechanism is
activated when a process gets -EAGAIN (activating this multiple times is
harmless, if a bit wasteful) and deactivated by the last process still
waiting.
The module name was changed from "random" to "hw_random" in order for udev to
recognize it.
The sigio workaround needed some changes. sigio_broken was added for cases
when we know that async notification doesn't work. This is now called from
maybe_sigio_broken, which deals with pts devices.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Reintroduce uml_kmalloc for the benefit of UML libc code. The
previous tactic of declaring __kmalloc so it could be called directly
from the libc side of the house turned out to be getting too intimate
with slab, and it doesn't work with slob.
So, the uml_kmalloc wrapper is back. It calls kmalloc or whatever
that translates into, and libc code calls it.
kfree is left alone since that still works, leaving a somewhat
inconsistent API.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Style fixes in arch/um/os-Linux/irq.c and arch/um/os-Linux/sigio.c:
Updated copyrights
trimmed includes
added severity indicators to printks
CodingStyle fixes
turned an bunch of panics into printks
call some libc functions directly instead of going through the
os_* wrappers
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Lucas Woods <woodzy@gmail.com>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch also does some improvements for uml code. Improvements include
dropping unnecessary cast, killing some unnecessary code and still some
constifying for pointers etc..
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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UML had two wrapper procedures for kmalloc, um_kmalloc and um_kmalloc_atomic
because the flag constants weren't available in userspace code.
kern_constants.h had made kernel constants available for a long time, so there
is no need for these wrappers any more. Rather, userspace code calls kmalloc
directly with the userspace versions of the gfp flags.
kmalloc isn't a real procedure, so I had to essentially copy the inline
wrapper around __kmalloc.
vmalloc also had its own wrapper for no good reason. This is now gone.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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run_helper and run_helper_thread had arguments which were the same in all
callers. run_helper's stack_out was always NULL and run_helper_thread's
stack_order was always 0. These are now gone, and the constants folded
into the code.
Also fixed leaks of the helper stack in the AIO and SIGIO code.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch converts calls in the os layer to os_{read,write}_file to calls
directly to libc read() and write() where it is clear that the I/O buffer is
in the kernel.
We can do that here instead of calling os_{read,write}_file_k since we are in
libc code and can call libc directly.
With the change in the calls, error handling needs to be changed to refer to
errno directly rather than the return value of the call.
CATCH_EINTR wrappers were also added where needed.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch lays some groundwork for the next one, which converts calls to
os_{read,write}_file into {read,write}, by doing some tidying in the affected
areas.
do_not_aio gets restructured to make the final result a bit cleaner.
There are also whitespace and other formatting fixes, fixes in error messages,
and a typo fix.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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user_util.h isn't needed any more, so delete it and remove all includes of it.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch narrows the sigio interface. The boot-time SIGIO testing used to
be in start_up.c, which meant that pty_output_sigio and pty_close_sigio needed
to be global. By moving that code here, those can become static and the
declarations moved from user_util.h.
os_check_bugs is also here because it only does the SIGIO checking. If it
does more, it'll probably move back to start_up.c.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In the 2.6.20 hang patch, I accidentally threw out an error message.
This puts it back.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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A previous cleanup misused need_poll, which had a fairly broken interface.
It implemented a growable array, changing the used elements count itself,
but leaving it up to the caller to fill in the actual elements, including
the entire array if the array had to be reallocated. This worked because
the previous users were switching between two such structures, and the
elements were copied from the inactive array to the active array after
making sure the active array had enough room.
maybe_sigio_broken was made to use need_poll, but it was operating on a
single array, so when the buffer was reallocated, the previous contents
were lost.
This patch makes need_poll implement more sane semantics. It merely
assures that the array is of the proper size and that the contents are
preserved. It is up to the caller to adjust the used elements count and to
ensure that the proper elements are resent.
This manifested itself as a hang in 2.6.20 as the uninitialized buffer
convinced UML that one of its own file descriptors didn't support SIGIO and
needed to be watched by poll in a separate thread. The result was an
interrupt flood as control traffic over this descriptor sparked interrupts,
which resulted in more control traffic, ad nauseum.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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user.h is too generic a header name. I've split out allocation routines from
it.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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- Various cleanups in the sigio code.
- Removed explicit zero-initializations of a few structures.
- Improved some error messages.
- An API change - there was an asymmetry between reactivate_fd calling
maybe_sigio_broken, which goes through all the machinery of figuring out if
a file descriptor supports SIGIO and applying the workaround to it if not,
and deactivate_fd, which just turns off the descriptor.
This is changed so that only activate_fd calls maybe_sigio_broken, when
the descriptor is first seen. reactivate_fd now calls add_sigio_fd, which
is symmetric with ignore_sigio_fd.
This removes a recursion which makes a critical section look more critical
than it really was, obsoleting a big comment to that effect. This requires
keeping track of all descriptors which are getting the SIGIO treatment, not
just the ones being polled at any given moment, so that reactivate_fd,
through add_sigio_fd, doesn't try to tell the SIGIO thread about descriptors
it doesn't care about.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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A few sigio-related things can be made static.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This fixes an exitcall ordering bug - calls to ignore_sigio_fd can come from
exitcalls that come after the sigio thread has been killed. This would cause
shutdown to hang or crash.
Fixed by having ignore_sigio_fd check that the thread is present before trying
to communicate with it.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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os_isatty can be made to disappear by moving maybe_sigio_broken from kernel to
user code. This also lets write_sigio_workaround become static.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Move a call to kfree on a local variable out of a spinlock - there's no need
to have it in. Done on a just merged patch.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This fixes a race in the starting of write_sigio_thread. Previously, some of
the data needed by the thread was initialized after the clone. If the thread
ran immediately, it would see the uninitialized data, including an empty
pollfds, which would cause it to hang.
We move the data initialization to before the clone, and adjust the error
paths and cleanup accordingly.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The serial UML OS-abstraction layer patch (um/kernel dir).
This moves sigio_user.c to os-Linux dir
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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