[ Upstream commit 6a85e34c4d07d2ec0c153067baff338ac0db55ca ]
Make it match its definition (size_t vs unsigned long). And declare
it in a shared header to fix the -Wmissing-prototypes warning, as it
is defined in the user code and called in the kernel code.
Fixes: 5b301409e8 ("UML: add support for KASAN under x86_64")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3144013e48f4f6e5127223c4ebc488016815dedb ]
The get_thread_reg function is defined in the user code, and is
called by the kernel code. It should be declared in a shared header.
Fixes: dbba7f704a ("um: stop polluting the namespace with registers.h contents")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 2cbade17b18c0f0fd9963f26c9fc9b057eb1cb3a ]
The __switch_mm function is defined in the user code, and is called
by the kernel code. It should be declared in a shared header.
Fixes: 4dc706c2f2 ("um: take um_mmu.h to asm/mmu.h, clean asm/mmu_context.h a bit")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 68fb3ca0e408e00db1c3f8fccdfa19e274c033be upstream.
We've had issues with gcc and 'asm goto' before, and we created a
'asm_volatile_goto()' macro for that in the past: see commits
3f0116c323 ("compiler/gcc4: Add quirk for 'asm goto' miscompilation
bug") and a9f180345f ("compiler/gcc4: Make quirk for
asm_volatile_goto() unconditional").
Then, much later, we ended up removing the workaround in commit
43c249ea0b ("compiler-gcc.h: remove ancient workaround for gcc PR
58670") because we no longer supported building the kernel with the
affected gcc versions, but we left the macro uses around.
Now, Sean Christopherson reports a new version of a very similar
problem, which is fixed by re-applying that ancient workaround. But the
problem in question is limited to only the 'asm goto with outputs'
cases, so instead of re-introducing the old workaround as-is, let's
rename and limit the workaround to just that much less common case.
It looks like there are at least two separate issues that all hit in
this area:
(a) some versions of gcc don't mark the asm goto as 'volatile' when it
has outputs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98619https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110420
which is easy to work around by just adding the 'volatile' by hand.
(b) Internal compiler errors:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110422
which are worked around by adding the extra empty 'asm' as a
barrier, as in the original workaround.
but the problem Sean sees may be a third thing since it involves bad
code generation (not an ICE) even with the manually added 'volatile'.
The same old workaround works for this case, even if this feels a
bit like voodoo programming and may only be hiding the issue.
Reported-and-tested-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/all/20240208220604.140859-1-seanjc@google.com/
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Andrew Pinski <quic_apinski@quicinc.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 541d4e4d435c8b9bfd29f70a1da4a2db97794e0a ]
__cant_sleep was already used and exported by the scheduler.
The name had to be changed to a UML specific one.
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Reviewed-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
Pull UML updates from Richard Weinberger:
- KASAN support for x86_64
- noreboot command line option, just like qemu's -no-reboot
- Various fixes and cleanups
* tag 'for-linus-5.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: include sys/types.h for size_t
um: Replace to_phys() and to_virt() with less generic function names
um: Add missing apply_returns()
um: add "noreboot" command line option for PANIC_TIMEOUT=-1 setups
um: include linux/stddef.h for __always_inline
UML: add support for KASAN under x86_64
mm: Add PAGE_ALIGN_DOWN macro
um: random: Don't initialise hwrng struct with zero
um: remove unused mm_copy_segments
um: remove unused variable
um: Remove straying parenthesis
um: x86: print RIP with symbol
arch: um: Fix build for statically linked UML w/ constructors
x86/um: Kconfig: Fix indentation
um/drivers: Kconfig: Fix indentation
um: Kconfig: Fix indentation
Pull pci updates from Bjorn Helgaas:
"Enumeration:
- Consolidate duplicated 'next function' scanning and extend to allow
'isolated functions' on s390, similar to existing hypervisors
(Niklas Schnelle)
Resource management:
- Implement pci_iobar_pfn() for sparc, which allows us to remove the
sparc-specific pci_mmap_page_range() and pci_mmap_resource_range().
This removes the ability to map the entire PCI I/O space using
/proc/bus/pci, but we believe that's already been broken since
v2.6.28 (Arnd Bergmann)
- Move common PCI definitions to asm-generic/pci.h and rework others
to be be more specific and more encapsulated in arches that need
them (Stafford Horne)
Power management:
- Convert drivers to new *_PM_OPS macros to avoid need for '#ifdef
CONFIG_PM_SLEEP' or '__maybe_unused' (Bjorn Helgaas)
Virtualization:
- Add ACS quirk for Broadcom BCM5750x multifunction NICs that isolate
the functions but don't advertise an ACS capability (Pavan Chebbi)
Error handling:
- Clear PCI Status register during enumeration in case firmware left
errors logged (Kai-Heng Feng)
- When we have native control of AER, enable error reporting for all
devices that support AER. Previously only a few drivers enabled
this (Stefan Roese)
- Keep AER error reporting enabled for switches. Previously we
enabled this during enumeration but immediately disabled it (Stefan
Roese)
- Iterate over error counters instead of error strings to avoid
printing junk in AER sysfs counters (Mohamed Khalfella)
ASPM:
- Remove pcie_aspm_pm_state_change() so ASPM config changes, e.g.,
via sysfs, are not lost across power state changes (Kai-Heng Feng)
Endpoint framework:
- Don't stop an EPC when unbinding an EPF from it (Shunsuke Mie)
Endpoint embedded DMA controller driver:
- Simplify and clean up support for the DesignWare embedded DMA
(eDMA) controller (Frank Li, Serge Semin)
Broadcom STB PCIe controller driver:
- Avoid config space accesses when link is down because we can't
recover from the CPU aborts these cause (Jim Quinlan)
- Look for power regulators described under Root Ports in DT and
enable them before scanning the secondary bus (Jim Quinlan)
- Disable/enable regulators in suspend/resume (Jim Quinlan)
Freescale i.MX6 PCIe controller driver:
- Simplify and clean up clock and PHY management (Richard Zhu)
- Disable/enable regulators in suspend/resume (Richard Zhu)
- Set PCIE_DBI_RO_WR_EN before writing DBI registers (Richard Zhu)
- Allow speeds faster than Gen2 (Richard Zhu)
- Make link being down a non-fatal error so controller probe doesn't
fail if there are no Endpoints connected (Richard Zhu)
Loongson PCIe controller driver:
- Add ACPI and MCFG support for Loongson LS7A (Huacai Chen)
- Avoid config reads to non-existent LS2K/LS7A devices because a
hardware defect causes machine hangs (Huacai Chen)
- Work around LS7A integrated devices that report incorrect Interrupt
Pin values (Jianmin Lv)
Marvell Aardvark PCIe controller driver:
- Add support for AER and Slot capability on emulated bridge (Pali
Rohár)
MediaTek PCIe controller driver:
- Add Airoha EN7532 to DT binding (John Crispin)
- Allow building of driver for ARCH_AIROHA (Felix Fietkau)
MediaTek PCIe Gen3 controller driver:
- Print decoded LTSSM state when the link doesn't come up (Jianjun
Wang)
NVIDIA Tegra194 PCIe controller driver:
- Convert DT binding to json-schema (Vidya Sagar)
- Add DT bindings and driver support for Tegra234 Root Port and
Endpoint mode (Vidya Sagar)
- Fix some Root Port interrupt handling issues (Vidya Sagar)
- Set default Max Payload Size to 256 bytes (Vidya Sagar)
- Fix Data Link Feature capability programming (Vidya Sagar)
- Extend Endpoint mode support to devices beyond Controller-5 (Vidya
Sagar)
Qualcomm PCIe controller driver:
- Rework clock, reset, PHY power-on ordering to avoid hangs and
improve consistency (Robert Marko, Christian Marangi)
- Move pipe_clk handling to PHY drivers (Dmitry Baryshkov)
- Add IPQ60xx support (Selvam Sathappan Periakaruppan)
- Allow ASPM L1 and substates for 2.7.0 (Krishna chaitanya chundru)
- Add support for more than 32 MSI interrupts (Dmitry Baryshkov)
Renesas R-Car PCIe controller driver:
- Convert DT binding to json-schema (Herve Codina)
- Add Renesas RZ/N1D (R9A06G032) to rcar-gen2 DT binding and driver
(Herve Codina)
Samsung Exynos PCIe controller driver:
- Fix phy-exynos-pcie driver so it follows the 'phy_init() before
phy_power_on()' PHY programming model (Marek Szyprowski)
Synopsys DesignWare PCIe controller driver:
- Simplify and clean up the DWC core extensively (Serge Semin)
- Fix an issue with programming the ATU for regions that cross a 4GB
boundary (Serge Semin)
- Enable the CDM check if 'snps,enable-cdm-check' exists; previously
we skipped it if 'num-lanes' was absent (Serge Semin)
- Allocate a 32-bit DMA-able page to be MSI target instead of using a
driver data structure that may not be addressable with 32-bit
address (Will McVicker)
- Add DWC core support for more than 32 MSI interrupts (Dmitry
Baryshkov)
Xilinx Versal CPM PCIe controller driver:
- Add DT binding and driver support for Versal CPM5 Gen5 Root Port
(Bharat Kumar Gogada)"
* tag 'pci-v5.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (150 commits)
PCI: imx6: Support more than Gen2 speed link mode
PCI: imx6: Set PCIE_DBI_RO_WR_EN before writing DBI registers
PCI: imx6: Reformat suspend callback to keep symmetric with resume
PCI: imx6: Move the imx6_pcie_ltssm_disable() earlier
PCI: imx6: Disable clocks in reverse order of enable
PCI: imx6: Do not hide PHY driver callbacks and refine the error handling
PCI: imx6: Reduce resume time by only starting link if it was up before suspend
PCI: imx6: Mark the link down as non-fatal error
PCI: imx6: Move regulator enable out of imx6_pcie_deassert_core_reset()
PCI: imx6: Turn off regulator when system is in suspend mode
PCI: imx6: Call host init function directly in resume
PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks
PCI: imx6: Propagate .host_init() errors to caller
PCI: imx6: Collect clock enables in imx6_pcie_clk_enable()
PCI: imx6: Factor out ref clock disable to match enable
PCI: imx6: Move imx6_pcie_clk_disable() earlier
PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier
PCI: imx6: Move PHY management functions together
PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type() earlier
PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()
...
The archrandom interface was originally designed for x86, which supplies
RDRAND/RDSEED for receiving random words into registers, resulting in
one function to generate an int and another to generate a long. However,
other architectures don't follow this.
On arm64, the SMCCC TRNG interface can return between one and three
longs. On s390, the CPACF TRNG interface can return arbitrary amounts,
with four longs having the same cost as one. On UML, the os_getrandom()
interface can return arbitrary amounts.
So change the api signature to take a "max_longs" parameter designating
the maximum number of longs requested, and then return the number of
longs generated.
Since callers need to check this return value and loop anyway, each arch
implementation does not bother implementing its own loop to try again to
fill the maximum number of longs. Additionally, all existing callers
pass in a constant max_longs parameter. Taken together, these two things
mean that the codegen doesn't really change much for one-word-at-a-time
platforms, while performance is greatly improved on platforms such as
s390.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
The isa_dma_bridge_buggy symbol is only used for x86_32, and only x86_32
platforms or quirks ever set it.
Add a new linux/isa-dma.h header that #defines isa_dma_bridge_buggy to 0
except on x86_32, where we keep it as a variable, and remove all the arch-
specific definitions.
[bhelgaas: commit log]
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Link: https://lore.kernel.org/r/20220722214944.831438-3-shorne@gmail.com
Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
pci_get_legacy_ide_irq() is only used on platforms that support PNP, so
many architectures define it but never use it. Replace uses of it with
ATA_PRIMARY_IRQ() and ATA_SECONDARY_IRQ(), which provide the same
functionality.
Since pci_get_legacy_ide_irq() is no longer used, remove all the
architecture-specific definitions of it as well as asm-generic/pci.h, which
only provides pci_get_legacy_ide_irq()
[bhelgaas: commit log]
Co-developed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220722214944.831438-2-shorne@gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Pierre Morel <pmorel@linux.ibm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
UML generally does not provide access to special CPU instructions like
RDRAND, and execution tends to be rather deterministic, with no real
hardware interrupts, making good randomness really very hard, if not
all together impossible. Not only is this a security eyebrow raiser, but
it's also quite annoying when trying to do various pieces of UML-based
automation that takes a long time to boot, if ever.
Fix this by trivially calling getrandom() in the host and using that
seed as "bootloader randomness", which initializes the rng immediately
at UML boot.
The old behavior can be restored the same way as on any other arch, by
way of CONFIG_TRUST_BOOTLOADER_RANDOMNESS=n or
random.trust_bootloader=0. So seen from that perspective, this just
makes UML act like other archs, which is positive in its own right.
Additionally, wire up arch_get_random_{int,long}() in the same way, so
that reseeds can also make use of the host RNG, controllable by
CONFIG_TRUST_CPU_RANDOMNESS and random.trust_cpu, per usual.
Cc: stable@vger.kernel.org
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Usually size_t comes from sys/types.h, not stddef.h. This code likely
worked only because something else in its usage chain was pulling in
sys/types.h. stddef.h is still required for NULL, however, so note this.
Cc: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
to_virt() and to_phys() are very generic and may be defined by drivers.
As it turns out, commit 9409c9b670 ("pmem: refactor pmem_clear_poison()")
did exactly that. This results in build errors such as the following
when trying to build um:allmodconfig.
drivers/nvdimm/pmem.c: In function ‘pmem_dax_zero_page_range’:
./arch/um/include/asm/page.h:105:20: error:
too few arguments to function ‘to_phys’
105 | #define __pa(virt) to_phys((void *) (unsigned long) (virt))
| ^~~~~~~
Use less generic function names for the um specific to_phys() and to_virt()
functions to fix the problem and to avoid similar problems in the future.
Fixes: 9409c9b670 ("pmem: refactor pmem_clear_poison()")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Make KASAN run on User Mode Linux on x86_64.
The UML-specific KASAN initializer uses mmap to map the ~16TB of shadow
memory to the location defined by KASAN_SHADOW_OFFSET. kasan_init()
utilizes constructors to initialize KASAN before main().
The location of the KASAN shadow memory, starting at
KASAN_SHADOW_OFFSET, can be configured using the KASAN_SHADOW_OFFSET
option. The default location of this offset is 0x100000000000, which
keeps it out-of-the-way even on UML setups with more "physical" memory.
For low-memory setups, 0x7fff8000 can be used instead, which fits in an
immediate and is therefore faster, as suggested by Dmitry Vyukov. There
is usually enough free space at this location; however, it is a config
option so that it can be easily changed if needed.
Note that, unlike KASAN on other architectures, vmalloc allocations
still use the shadow memory allocated upfront, rather than allocating
and free-ing it per-vmalloc allocation.
If another architecture chooses to go down the same path, we should
replace the checks for CONFIG_UML with something more generic, such
as:
- A CONFIG_KASAN_NO_SHADOW_ALLOC option, which architectures could set
- or, a way of having architecture-specific versions of these vmalloc
and module shadow memory allocation options.
Also note that, while UML supports both KASAN in inline mode
(CONFIG_KASAN_INLINE) and static linking (CONFIG_STATIC_LINK), it does
not support both at the same time.
Signed-off-by: Patricia Alfonso <trishalfonso@google.com>
Co-developed-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
It was already removed by commit c17c02040b ("arch: remove unused
*_segments() macros/functions") but seems to have been accidentally
reintroduced by commit 0500871f21 ("Construct init thread stack in the
linker script rather than by union"). Remove it for good.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Richard Weinberger <richard@nod.at>
Commit e3a33af812 ("um: fix and optimize xor select template for CONFIG64 and timetravel mode")
caused a build regression when CONFIG_XOR_BLOCKS and CONFIG_UML_TIME_TRAVEL_SUPPORT
are selected.
Fix it by removing the straying parenthesis.
Cc: stable@vger.kernel.org
Fixes: e3a33af812 ("um: fix and optimize xor select template for CONFIG64 and timetravel mode")
Signed-off-by: Benjamin Beichler <benjamin.beichler@uni-rostock.de>
[rw: Added commit message]
Signed-off-by: Richard Weinberger <richard@nod.at>
The UML function names to_virt() and to_phys() are exposed by UML
headers, and are very generic and may be defined by drivers. As it
turns out, commit 9409c9b670 ("pmem: refactor pmem_clear_poison()")
did exactly that.
This results in build errors such as the following when trying to build
um:allmodconfig:
drivers/nvdimm/pmem.c: In function ‘pmem_dax_zero_page_range’:
./arch/um/include/asm/page.h:105:20: error: too few arguments to function ‘to_phys’
105 | #define __pa(virt) to_phys((void *) (unsigned long) (virt))
| ^~~~~~~
Use less generic function names for the um specific to_phys() and
to_virt() functions to fix the problem and to avoid similar problems in
the future.
Fixes: 9409c9b670 ("pmem: refactor pmem_clear_poison()")
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ptrace_stop cleanups from Eric Biederman:
"While looking at the ptrace problems with PREEMPT_RT and the problems
Peter Zijlstra was encountering with ptrace in his freezer rewrite I
identified some cleanups to ptrace_stop that make sense on their own
and move make resolving the other problems much simpler.
The biggest issue is the habit of the ptrace code to change
task->__state from the tracer to suppress TASK_WAKEKILL from waking up
the tracee. No other code in the kernel does that and it is straight
forward to update signal_wake_up and friends to make that unnecessary.
Peter's task freezer sets frozen tasks to a new state TASK_FROZEN and
then it stores them by calling "wake_up_state(t, TASK_FROZEN)" relying
on the fact that all stopped states except the special stop states can
tolerate spurious wake up and recover their state.
The state of stopped and traced tasked is changed to be stored in
task->jobctl as well as in task->__state. This makes it possible for
the freezer to recover tasks in these special states, as well as
serving as a general cleanup. With a little more work in that
direction I believe TASK_STOPPED can learn to tolerate spurious wake
ups and become an ordinary stop state.
The TASK_TRACED state has to remain a special state as the registers
for a process are only reliably available when the process is stopped
in the scheduler. Fundamentally ptrace needs acess to the saved
register values of a task.
There are bunch of semi-random ptrace related cleanups that were found
while looking at these issues.
One cleanup that deserves to be called out is from commit 57b6de08b5
("ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs"). This
makes a change that is technically user space visible, in the handling
of what happens to a tracee when a tracer dies unexpectedly. According
to our testing and our understanding of userspace nothing cares that
spurious SIGTRAPs can be generated in that case"
* tag 'ptrace_stop-cleanup-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
sched,signal,ptrace: Rework TASK_TRACED, TASK_STOPPED state
ptrace: Always take siglock in ptrace_resume
ptrace: Don't change __state
ptrace: Admit ptrace_stop can generate spuriuos SIGTRAPs
ptrace: Document that wait_task_inactive can't fail
ptrace: Reimplement PTRACE_KILL by always sending SIGKILL
signal: Use lockdep_assert_held instead of assert_spin_locked
ptrace: Remove arch_ptrace_attach
ptrace/xtensa: Replace PT_SINGLESTEP with TIF_SINGLESTEP
ptrace/um: Replace PT_DTRACE with TIF_SINGLESTEP
signal: Replace __group_send_sig_info with send_signal_locked
signal: Rename send_signal send_signal_locked
Pull UML updates from Richard Weinberger:
- Various cleanups and fixes: xterm, serial line, time travel
- Set ARCH_HAS_GCOV_PROFILE_ALL
* tag 'for-linus-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
um: Fix out-of-bounds read in LDT setup
um: chan_user: Fix winch_tramp() return value
um: virtio_uml: Fix broken device handling in time-travel
um: line: Use separate IRQs per line
um: Enable ARCH_HAS_GCOV_PROFILE_ALL
um: Use asm-generic/dma-mapping.h
um: daemon: Make default socket configurable
um: xterm: Make default terminal emulator configurable
