search_module_extables() returns an exception_table_entry belonging to a
module. The lookup via __module_address() can be performed with RCU
protection.
The returned exception_table_entry remains valid because the passed
address usually belongs to a module that is currently executed. So the
module can not be removed because "something else" holds a reference to
it, ensuring that it can not be removed.
Exceptions here are:
- kprobe, acquires a reference on the module beforehand
- MCE, invokes the function from within a timer and the RCU lifetime
guarantees (of the timer) are sufficient.
Therefore it is safe to return the exception_table_entry outside the RCU
section which provided the module.
Use RCU for the lookup in search_module_extables() and update the
comment.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-14-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
mod_find() uses either the modules list to find a module or a tree
lookup (CONFIG_MODULES_TREE_LOOKUP). The list and the tree can both be
iterated under RCU assumption (as well as RCU-sched).
Remove module_assert_mutex_or_preempt() from __module_address() and
entirely since __module_address() is the last user.
Update comments.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-13-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
module_assert_mutex_or_preempt() is not needed in find_symbol(). The
function checks for RCU-sched or the module_mutex to be acquired. The
list_for_each_entry_rcu() below does the same check.
Remove module_assert_mutex_or_preempt() from try_add_tainted_module().
Use RCU protection to invoke find_symbol() and update callers.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-11-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
The modules list and module::kallsyms can be accessed under RCU
assumption.
Use rcu_dereference() to reference the kallsyms pointer in
find_kallsyms_symbol(). Use a RCU section instead of preempt_disable in
callers of find_kallsyms_symbol(). Keep the preempt-disable in
module_address_lookup() due to __module_address().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-5-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
add_kallsyms() assigns the RCU pointer module::kallsyms and setups the
structures behind it which point to init-data. The module was not
published yet, nothing can see the kallsyms pointer and the data behind
it. Also module's init function was not yet invoked.
There is no need to use rcu_dereference() here, it is just to keep
checkers quiet. The whole RCU read section is also not needed.
Use a local kallsyms pointer and setup the data structures. Assign that
pointer to the data structure at the end via rcu_assign_pointer().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-4-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
The RCU usage in module was introduced in commit d72b37513c ("Remove
stop_machine during module load v2") and it claimed not to be RCU but
similar. Then there was another improvement in commit e91defa26c
("module: don't use stop_machine on module load"). It become a mix of
RCU and RCU-sched and was eventually fixed 0be964be0d ("module:
Sanitize RCU usage and locking"). Later RCU & RCU-sched was merged in
commit cb2f55369d ("modules: Replace synchronize_sched() and
call_rcu_sched()") so that was aligned.
Looking at it today, there is still leftovers. The preempt_disable() was
used instead rcu_read_lock_sched(). The RCU & RCU-sched merge was not
complete as there is still rcu_dereference_sched() for module::kallsyms.
The RCU-list modules and unloaded_tainted_modules are always accessed
under RCU protection or the module_mutex. The modules list iteration can
always happen safely because the module will not disappear.
Once the module is removed (free_module()) then after removing the
module from the list, there is a synchronize_rcu() which waits until
every RCU reader left the section. That means iterating over the list
within a RCU-read section is enough, there is no need to disable
preemption. module::kallsyms is first assigned in add_kallsyms() before
the module is added to the list. At this point, it points to init data.
This pointer is later updated and before the init code is removed there
is also synchronize_rcu() in do_free_init(). That means A RCU read lock
is enough for protection and rcu_dereference() can be safely used.
Convert module code and its users step by step. Update comments and
convert print_modules() to use RCU.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-3-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Pull Kbuild fixes from Masahiro Yamada:
- Use the specified $(LD) when building userprogs with Clang
- Pass the correct target triple when compile-testing UAPI headers
with Clang
- Fix pacman-pkg build error with KBUILD_OUTPUT
* tag 'kbuild-fixes-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: install-extmod-build: Fix build when specifying KBUILD_OUTPUT
docs: Kconfig: fix defconfig description
kbuild: hdrcheck: fix cross build with clang
kbuild: userprogs: use correct lld when linking through clang
Pull USB fixes from Greg KH:
"Here are some small USB driver fixes for some reported issues. These
contain:
- typec driver fixes
- dwc3 driver fixes
- xhci driver fixes
- renesas controller fixes
- gadget driver fixes
- a new USB quirk added
All of these have been in linux-next with no reported issues"
* tag 'usb-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
usb: typec: ucsi: Fix NULL pointer access
usb: quirks: Add DELAY_INIT and NO_LPM for Prolific Mass Storage Card Reader
usb: xhci: Fix host controllers "dying" after suspend and resume
usb: dwc3: Set SUSPENDENABLE soon after phy init
usb: hub: lack of clearing xHC resources
usb: renesas_usbhs: Flush the notify_hotplug_work
usb: renesas_usbhs: Use devm_usb_get_phy()
usb: renesas_usbhs: Call clk_put()
usb: dwc3: gadget: Prevent irq storm when TH re-executes
usb: gadget: Check bmAttributes only if configuration is valid
xhci: Restrict USB4 tunnel detection for USB3 devices to Intel hosts
usb: xhci: Enable the TRB overfetch quirk on VIA VL805
usb: gadget: Fix setting self-powered state on suspend
usb: typec: ucsi: increase timeout for PPM reset operations
acpi: typec: ucsi: Introduce a ->poll_cci method
usb: typec: tcpci_rt1711h: Unmask alert interrupts to fix functionality
usb: gadget: Set self-powered based on MaxPower and bmAttributes
usb: gadget: u_ether: Set is_suspend flag if remote wakeup fails
usb: atm: cxacru: fix a flaw in existing endpoint checks
Pull driver core fix from Greg KH:
"Here is a single driver core fix that resolves a reported memory leak.
It's been in linux-next for 2 weeks now with no reported problems"
* tag 'driver-core-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
drivers: core: fix device leak in __fw_devlink_relax_cycles()
Pull char/misc/IIO driver fixes from Greg KH:
"Here are a number of misc and char and iio driver fixes that have been
sitting in my tree for way too long. They contain:
- iio driver fixes for reported issues
- regression fix for rtsx_usb card reader
- mei and mhi driver fixes
- small virt driver fixes
- ntsync permissions fix
- other tiny driver fixes for reported problems.
All of these have been in linux-next for quite a while with no
reported issues"
* tag 'char-misc-6.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (30 commits)
Revert "drivers/card_reader/rtsx_usb: Restore interrupt based detection"
ntsync: Check wait count based on byte size.
bus: simple-pm-bus: fix forced runtime PM use
char: misc: deallocate static minor in error path
eeprom: digsy_mtc: Make GPIO lookup table match the device
drivers: virt: acrn: hsm: Use kzalloc to avoid info leak in pmcmd_ioctl
binderfs: fix use-after-free in binder_devices
slimbus: messaging: Free transaction ID in delayed interrupt scenario
vbox: add HAS_IOPORT dependency
cdx: Fix possible UAF error in driver_override_show()
intel_th: pci: Add Panther Lake-P/U support
intel_th: pci: Add Panther Lake-H support
intel_th: pci: Add Arrow Lake support
intel_th: msu: Fix less trivial kernel-doc warnings
intel_th: msu: Fix kernel-doc warnings
MAINTAINERS: change maintainer for FSI
ntsync: Set the permissions to be 0666
bus: mhi: host: pci_generic: Use pci_try_reset_function() to avoid deadlock
mei: vsc: Use "wakeuphostint" when getting the host wakeup GPIO
mei: me: add panther lake P DID
...
Pull KVM fixes from Paolo Bonzini:
"arm64:
- Fix a couple of bugs affecting pKVM's PSCI relay implementation
when running in the hVHE mode, resulting in the host being entered
with the MMU in an unknown state, and EL2 being in the wrong mode
x86:
- Set RFLAGS.IF in C code on SVM to get VMRUN out of the STI shadow
- Ensure DEBUGCTL is context switched on AMD to avoid running the
guest with the host's value, which can lead to unexpected bus lock
#DBs
- Suppress DEBUGCTL.BTF on AMD (to match Intel), as KVM doesn't
properly emulate BTF. KVM's lack of context switching has meant BTF
has always been broken to some extent
- Always save DR masks for SNP vCPUs if DebugSwap is *supported*, as
the guest can enable DebugSwap without KVM's knowledge
- Fix a bug in mmu_stress_tests where a vCPU could finish the "writes
to RO memory" phase without actually generating a write-protection
fault
- Fix a printf() goof in the SEV smoke test that causes build
failures with -Werror
- Explicitly zero EAX and EBX in CPUID.0x8000_0022 output when
PERFMON_V2 isn't supported by KVM"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: Explicitly zero EAX and EBX when PERFMON_V2 isn't supported by KVM
KVM: selftests: Fix printf() format goof in SEV smoke test
KVM: selftests: Ensure all vCPUs hit -EFAULT during initial RO stage
KVM: SVM: Don't rely on DebugSwap to restore host DR0..DR3
KVM: SVM: Save host DR masks on CPUs with DebugSwap
KVM: arm64: Initialize SCTLR_EL1 in __kvm_hyp_init_cpu()
KVM: arm64: Initialize HCR_EL2.E2H early
KVM: x86: Snapshot the host's DEBUGCTL after disabling IRQs
KVM: SVM: Manually context switch DEBUGCTL if LBR virtualization is disabled
KVM: x86: Snapshot the host's DEBUGCTL in common x86
KVM: SVM: Suppress DEBUGCTL.BTF on AMD
KVM: SVM: Drop DEBUGCTL[5:2] from guest's effective value
KVM: selftests: Assert that STI blocking isn't set after event injection
KVM: SVM: Set RFLAGS.IF=1 in C code, to get VMRUN out of the STI shadow
KVM x86 fixes for 6.14-rcN #2
- Set RFLAGS.IF in C code on SVM to get VMRUN out of the STI shadow.
- Ensure DEBUGCTL is context switched on AMD to avoid running the guest with
the host's value, which can lead to unexpected bus lock #DBs.
- Suppress DEBUGCTL.BTF on AMD (to match Intel), as KVM doesn't properly
emulate BTF. KVM's lack of context switching has meant BTF has always been
broken to some extent.
- Always save DR masks for SNP vCPUs if DebugSwap is *supported*, as the guest
can enable DebugSwap without KVM's knowledge.
- Fix a bug in mmu_stress_tests where a vCPU could finish the "writes to RO
memory" phase without actually generating a write-protection fault.
- Fix a printf() goof in the SEV smoke test that causes build failures with
-Werror.
- Explicitly zero EAX and EBX in CPUID.0x8000_0022 output when PERFMON_V2
isn't supported by KVM.
KVM/arm64 fixes for 6.14, take #4
- Fix a couple of bugs affecting pKVM's PSCI relay implementation
when running in the hVHE mode, resulting in the host being entered
with the MMU in an unknown state, and EL2 being in the wrong mode.
Pull misc fixes from Andrew Morton:
"33 hotfixes. 24 are cc:stable and the remainder address post-6.13
issues or aren't considered necessary for -stable kernels.
26 are for MM and 7 are for non-MM.
- "mm: memory_failure: unmap poisoned folio during migrate properly"
from Ma Wupeng fixes a couple of two year old bugs involving the
migration of hwpoisoned folios.
- "selftests/damon: three fixes for false results" from SeongJae Park
fixes three one year old bugs in the SAMON selftest code.
The remainder are singletons and doubletons. Please see the individual
changelogs for details"
* tag 'mm-hotfixes-stable-2025-03-08-16-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (33 commits)
mm/page_alloc: fix uninitialized variable
rapidio: add check for rio_add_net() in rio_scan_alloc_net()
rapidio: fix an API misues when rio_add_net() fails
MAINTAINERS: .mailmap: update Sumit Garg's email address
Revert "mm/page_alloc.c: don't show protection in zone's ->lowmem_reserve[] for empty zone"
mm: fix finish_fault() handling for large folios
mm: don't skip arch_sync_kernel_mappings() in error paths
mm: shmem: remove unnecessary warning in shmem_writepage()
userfaultfd: fix PTE unmapping stack-allocated PTE copies
userfaultfd: do not block on locking a large folio with raised refcount
mm: zswap: use ATOMIC_LONG_INIT to initialize zswap_stored_pages
mm: shmem: fix potential data corruption during shmem swapin
mm: fix kernel BUG when userfaultfd_move encounters swapcache
selftests/damon/damon_nr_regions: sort collected regiosn before checking with min/max boundaries
selftests/damon/damon_nr_regions: set ops update for merge results check to 100ms
selftests/damon/damos_quota: make real expectation of quota exceeds
include/linux/log2.h: mark is_power_of_2() with __always_inline
NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback
mm, swap: avoid BUG_ON in relocate_cluster()
mm: swap: use correct step in loop to wait all clusters in wait_for_allocation()
...
Pull more x86 fixes from Ingo Molnar:
- Add more model IDs to the AMD microcode version check, more people
are hitting these checks
- Fix a Xen guest boot warning related to AMD northbridge setup
- Fix SEV guest bugs related to a recent changes in its locking logic
- Fix a missing definition of PTRS_PER_PMD that assembly builds can hit
* tag 'x86-urgent-2025-03-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode/AMD: Add some forgotten models to the SHA check
x86/mm: Define PTRS_PER_PMD for assembly code too
virt: sev-guest: Move SNP Guest Request data pages handling under snp_cmd_mutex
virt: sev-guest: Allocate request data dynamically
x86/amd_nb: Use rdmsr_safe() in amd_get_mmconfig_range()
Pull LoongArch fixes from Huacai Chen:
"Fix bugs in kernel build, hibernation, memory management and KVM"
* tag 'loongarch-fixes-6.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
LoongArch: KVM: Fix GPA size issue about VM
LoongArch: KVM: Reload guest CSR registers after sleep
LoongArch: KVM: Add interrupt checking for AVEC
LoongArch: Set hugetlb mmap base address aligned with pmd size
LoongArch: Set max_pfn with the PFN of the last page
LoongArch: Use polling play_dead() when resuming from hibernation
LoongArch: Eliminate superfluous get_numa_distances_cnt()
LoongArch: Convert unreachable() to BUG()
Physical address space is 48 bit on Loongson-3A5000 physical machine,
however it is 47 bit for VM on Loongson-3A5000 system. Size of physical
address space of VM is the same with the size of virtual user space (a
half) of physical machine.
Variable cpu_vabits represents user address space, kernel address space
is not included (user space and kernel space are both a half of total).
Here cpu_vabits, rather than cpu_vabits - 1, is to represent the size of
guest physical address space.
Also there is strict checking about page fault GPA address, inject error
if it is larger than maximum GPA address of VM.
Cc: stable@vger.kernel.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
On host, the HW guest CSR registers are lost after suspend and resume
operation. Since last_vcpu of boot CPU still records latest vCPU pointer
so that the guest CSR register skips to reload when boot CPU resumes and
vCPU is scheduled.
Here last_vcpu is cleared so that guest CSR registers will reload from
scheduled vCPU context after suspend and resume.
Cc: stable@vger.kernel.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
There is a newly added macro INT_AVEC with CSR ESTAT register, which is
bit 14 used for LoongArch AVEC support. AVEC interrupt status bit 14 is
supported with macro CSR_ESTAT_IS, so here replace the hard-coded value
0x1fff with macro CSR_ESTAT_IS so that the AVEC interrupt status is also
supported by KVM.
Cc: stable@vger.kernel.org
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
The current max_pfn equals to zero. In this case, it causes user cannot
get some page information through /proc filesystem such as kpagecount.
The following message is displayed by stress-ng test suite with command
"stress-ng --verbose --physpage 1 -t 1".
# stress-ng --verbose --physpage 1 -t 1
stress-ng: error: [1691] physpage: cannot read page count for address 0x134ac000 in /proc/kpagecount, errno=22 (Invalid argument)
stress-ng: error: [1691] physpage: cannot read page count for address 0x7ffff207c3a8 in /proc/kpagecount, errno=22 (Invalid argument)
stress-ng: error: [1691] physpage: cannot read page count for address 0x134b0000 in /proc/kpagecount, errno=22 (Invalid argument)
...
After applying this patch, the kernel can pass the test.
# stress-ng --verbose --physpage 1 -t 1
stress-ng: debug: [1701] physpage: [1701] started (instance 0 on CPU 3)
stress-ng: debug: [1701] physpage: [1701] exited (instance 0 on CPU 3)
stress-ng: debug: [1700] physpage: [1701] terminated (success)
Cc: stable@vger.kernel.org # 6.8+
Fixes: ff6c3d81f2 ("NUMA: optimize detection of memory with no node id assigned by firmware")
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
When CONFIG_RANDOM_KMALLOC_CACHES or other randomization infrastructrue
enabled, the idle_task's stack may different between the booting kernel
and target kernel. So when resuming from hibernation, an ACTION_BOOT_CPU
IPI wakeup the idle instruction in arch_cpu_idle_dead() and jump to the
interrupt handler. But since the stack pointer is changed, the interrupt
handler cannot restore correct context.
So rename the current arch_cpu_idle_dead() to idle_play_dead(), make it
as the default version of play_dead(), and the new arch_cpu_idle_dead()
call play_dead() directly. For hibernation, implement an arch-specific
hibernate_resume_nonboot_cpu_disable() to use the polling version (idle
instruction is replace by nop, and irq is disabled) of play_dead(), i.e.
poll_play_dead(), to avoid IPI handler corrupting the idle_task's stack
when resuming from hibernation.
This solution is a little similar to commit 406f992e4a ("x86 /
hibernate: Use hlt_play_dead() when resuming from hibernation").
Cc: stable@vger.kernel.org
Tested-by: Erpeng Xu <xuerpeng@uniontech.com>
Tested-by: Yuli Wang <wangyuli@uniontech.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
When compiling on LoongArch, there exists the following objtool warning
in arch/loongarch/kernel/machine_kexec.o:
kexec_reboot() falls through to next function crash_shutdown_secondary()
Avoid using unreachable() as it can (and will in the absence of UBSAN)
generate fall-through code. Use BUG() so we get a "break BRK_BUG" trap
(with unreachable annotation).
Cc: stable@vger.kernel.org # 6.12+
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Pull s390 fixes from Vasily Gorbik:
- Fix return address recovery of traced function in ftrace to ensure
reliable stack unwinding
- Fix compiler warnings and runtime crashes of vDSO selftests on s390
by introducing a dedicated GNU hash bucket pointer with correct
32-bit entry size
- Fix test_monitor_call() inline asm, which misses CC clobber, by
switching to an instruction that doesn't modify CC
* tag 's390-6.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/ftrace: Fix return address recovery of traced function
selftests/vDSO: Fix GNU hash table entry size for s390x
s390/traps: Fix test_monitor_call() inline assembly
Andy reported the following build warning from head_32.S:
In file included from arch/x86/kernel/head_32.S:29:
arch/x86/include/asm/pgtable_32.h:59:5: error: "PTRS_PER_PMD" is not defined, evaluates to 0 [-Werror=undef]
59 | #if PTRS_PER_PMD > 1
The reason is that on 2-level i386 paging the folded in PMD's
PTRS_PER_PMD constant is not defined in assembly headers,
only in generic MM C headers.
Instead of trying to fish out the definition from the generic
headers, just define it - it even has a comment for it already...
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/Z8oa8AUVyi2HWfo9@gmail.com
Pull slab fix from Vlastimil Babka:
- Stable fix for kmem_cache_destroy() called from a WQ_MEM_RECLAIM
workqueue causing a warning due to the new kvfree_rcu_barrier()
(Uladzislau Rezki)
* tag 'slab-for-6.14-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq
