linux-stable.git/arch/loongarch/kernel, branch linux-rolling-lts Linux kernel stable tree LoongArch: Add PIO for early access before ACPI PCI root register 2026-07-18T14:53:06+00:00 Huacai Chen chenhuacai@loongson.cn 2026-06-25T05:03:47+00:00 30d5d4eef35a9edf00d0ec005710c785594eeca2 commit 6061e65f95713b01f4313cda6637dfe3aa5412b4 upstream. For ACPI system we suppose the ISA/LPC PIO range is registered together with PCI root bridge. But the fact is there may be some early access to the ISA/LPC PIO range before ACPI PCI root register (most of them are due to abnormal BIOS). Unconditionally register the ISA/LPC PIO range usually causes ACPI PCI root register fail because of the address range confliction. So we add a pair of helpers: acpi_add_early_pio() to add PIO for early access, and acpi_remove_early_pio() to remove PIO before PCI root register. Since acpi_remove_early_pio() may be called multiple times, we add an acpi_pio flag to ensure PIO be removed only once. Cc: <stable@vger.kernel.org> Tested-by: Yuanzhen Gan <elysia-best@simplelinux.cn.eu.org> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6061e65f95713b01f4313cda6637dfe3aa5412b4 upstream.

For ACPI system we suppose the ISA/LPC PIO range is registered together
with PCI root bridge. But the fact is there may be some early access to
the ISA/LPC PIO range before ACPI PCI root register (most of them are
due to abnormal BIOS). Unconditionally register the ISA/LPC PIO range
usually causes ACPI PCI root register fail because of the address range
confliction. So we add a pair of helpers: acpi_add_early_pio() to add
PIO for early access, and acpi_remove_early_pio() to remove PIO before
PCI root register. Since acpi_remove_early_pio() may be called multiple
times, we add an acpi_pio flag to ensure PIO be removed only once.

Cc: <stable@vger.kernel.org>
Tested-by: Yuanzhen Gan <elysia-best@simplelinux.cn.eu.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: Report dying CPU to RCU in stop_this_cpu() 2026-07-04T11:44:19+00:00 Huacai Chen chenhuacai@loongson.cn 2026-06-25T05:03:49+00:00 90e254f18b8c224460082329dd5c42fd30995c2f commit f2539c56c74691e7a88af6372ba2b48c06ed2fe4 upstream. This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary CPUs in stop_this_cpu(). And the function marks the CPU offline for the scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps expecting a quiescent state from CPUs that are now spinning forever with interrupts disabled. As long as nothing waits for an RCU grace period after smp_send_stop() this is harmless, which is why it went unnoticed. However, since commit 91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt() returns false. Any irq_work_sync() issued in the reboot/shutdown/halt path after smp_send_stop() then blocks on a grace period that can never complete, hanging the reboot: WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on ... rcu: INFO: rcu_sched detected stalls on CPUs/tasks: rcu: Offline CPU 1 blocking current GP. rcu: Offline CPU 2 blocking current GP. rcu: Offline CPU 3 blocking current GP. This issue needs some hacks to reproduce, and it was not noticed on LoongArch because arch_irq_work_has_interrupt() usually returns true. Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring the generic CPU-hotplug offline path, so RCU stops waiting on the parked CPUs and grace periods can still complete. LoongArch shuts down all CPUs here without going through the CPU-hotplug mechanism, so this report is not otherwise issued. Cc: <stable@vger.kernel.org> Fixes: 91840be8f710 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT") Reviewed-by: Guo Ren <guoren@kernel.org> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f2539c56c74691e7a88af6372ba2b48c06ed2fe4 upstream.

This is a port of MIPS commit 9f3f3bdc6d9dac1 ("MIPS: smp: report dying
CPU to RCU in stop_this_cpu()"). smp_send_stop() parks all secondary
CPUs in stop_this_cpu(). And the function marks the CPU offline for the
scheduler via set_cpu_online(false) but never informs RCU, so RCU keeps
expecting a quiescent state from CPUs that are now spinning forever with
interrupts disabled.

As long as nothing waits for an RCU grace period after smp_send_stop()
this is harmless, which is why it went unnoticed. However, since commit
91840be8f710370 ("irq_work: Fix use-after-free in irq_work_single() on
PREEMPT_RT"), irq_work_sync() calls synchronize_rcu() on architectures
without an irq_work self-IPI, i.e. where arch_irq_work_has_interrupt()
returns false. Any irq_work_sync() issued in the reboot/shutdown/halt
path after smp_send_stop() then blocks on a grace period that can never
complete, hanging the reboot:

  WARNING: CPU: 0 PID: 15 at kernel/irq_work.c:144 irq_work_queue_on
  ...
  rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
  rcu: Offline CPU 1 blocking current GP.
  rcu: Offline CPU 2 blocking current GP.
  rcu: Offline CPU 3 blocking current GP.

This issue needs some hacks to reproduce, and it was not noticed on
LoongArch because arch_irq_work_has_interrupt() usually returns true.

Call rcutree_report_cpu_dead() once interrupts are disabled, mirroring
the generic CPU-hotplug offline path, so RCU stops waiting on the parked
CPUs and grace periods can still complete. LoongArch shuts down all CPUs
here without going through the CPU-hotplug mechanism, so this report is
not otherwise issued.

Cc: <stable@vger.kernel.org>
Fixes: 91840be8f710 ("irq_work: Fix use-after-free in irq_work_single() on PREEMPT_RT")
Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: kprobes: Fix handling of fatal unrecoverable recursions 2026-06-01T15:51:08+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2026-05-22T07:05:07+00:00 306ba9d0e5aa98465c2d5588f91994fbdf95c4d6 [ Upstream commit 1c856e158fd34ef2c4475a81c1dc386329989938 ] KPROBE_HIT_SS and KPROBE_REENTER are two types of fatal recursions that can not be safely recovered in kprobes. KPROBE_HIT_SS means that a kprobe is hit during single-stepping. At this point, the architecture-specific single-step context is already active. Nested single-stepping would corrupt the state, as the kprobe control block (kcb) and hardware registers cannot safely store multiple levels of stepping state. KPROBE_REENTER means that a third-level recursion occurs when a probe is hit while the system is already handling a nested probe (second- level). The kcb only provides a single slot (prev_kprobe) to backup the state. When a third probe is hit, there is no more space to save the state without corrupting the first-level backup. Kprobes work by replacing instructions with breakpoints. In order to execute the original instruction and continue, it must be moved to a temporary "single-step" slot. Since there is no backup space left to set up this slot safely, the CPU would be forced to return to the same original breakpoint address, triggering an endless loop. Currently, the code only prints a warning and returns. This leads to an infinite re-entry loop as the CPU repeatedly hits the same trap and a "stuck" CPU core because preemption was disabled at the start of the handler and never re-enabled in this early return path. Fix the logic by: 1. Merging KPROBE_HIT_SS and KPROBE_REENTER cases, as both represent fatal recursions that cannot be safely recovered. 2. Replacing WARN_ON_ONCE() with BUG() to terminate the system. This aligns LoongArch with other architectures (x86, arm64, riscv) and prevents stack overflow while providing diagnostic information. Fixes: 6d4cc40fb5f5 ("LoongArch: Add kprobes support") Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1c856e158fd34ef2c4475a81c1dc386329989938 ]

KPROBE_HIT_SS and KPROBE_REENTER are two types of fatal recursions that
can not be safely recovered in kprobes.

KPROBE_HIT_SS means that a kprobe is hit during single-stepping. At
this point, the architecture-specific single-step context is already
active. Nested single-stepping would corrupt the state, as the kprobe
control block (kcb) and hardware registers cannot safely store multiple
levels of stepping state.

KPROBE_REENTER means that a third-level recursion occurs when a probe
is hit while the system is already handling a nested probe (second-
level). The kcb only provides a single slot (prev_kprobe) to backup the
state. When a third probe is hit, there is no more space to save the
state without corrupting the first-level backup.

Kprobes work by replacing instructions with breakpoints. In order to
execute the original instruction and continue, it must be moved to a
temporary "single-step" slot. Since there is no backup space left to
set up this slot safely, the CPU would be forced to return to the same
original breakpoint address, triggering an endless loop.

Currently, the code only prints a warning and returns. This leads to
an infinite re-entry loop as the CPU repeatedly hits the same trap and
a "stuck" CPU core because preemption was disabled at the start of the
handler and never re-enabled in this early return path.

Fix the logic by:
1. Merging KPROBE_HIT_SS and KPROBE_REENTER cases, as both represent
   fatal recursions that cannot be safely recovered.
2. Replacing WARN_ON_ONCE() with BUG() to terminate the system. This
   aligns LoongArch with other architectures (x86, arm64, riscv) and
   prevents stack overflow while providing diagnostic information.

Fixes: 6d4cc40fb5f5 ("LoongArch: Add kprobes support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
LoongArch: kprobes: Use larch_insn_text_copy() to patch instructions 2026-06-01T15:50:47+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2026-05-22T07:05:07+00:00 f27a3b9aadfb53150a1b033f1d463f63ad800cf6 commit e3ef9a28f558d1cbf0b42d6dcd16c60da557562b upstream. On SMP systems, kprobe handlers would occasionally fail to execute on certain CPU cores. The issue is hard to reproduce and typically occurs randomly under high system load. The root cause is a software-side instruction hazard. According to the LoongArch Reference Manual, while the cache coherency is maintained by hardware, software must explicitly use the "IBAR" instruction to ensure the instruction fetch unit (IFU) observes the effects of recent stores. The current arch_arm_kprobe() and arch_disarm_kprobe() only execute the "IBAR" barrier (via flush_insn_slot -> local_flush_icache_range) on the local CPU. This leaves a vulnerable window where remote CPU cores may continue executing stale instructions from their pipelines or prefetch buffers, as they have not executed an "IBAR" since the code modification. Switch to larch_insn_text_copy() to fix this: 1. Synchronization: It uses stop_machine_cpuslocked() to synchronize all online CPUs, ensuring no CPU is executing the target code area during modification. 2. Visibility: By passing cpu_online_mask to stop_machine_cpuslocked(), the callback text_copy_cb() is executed on all online cores. Each CPU core invokes local_flush_icache_range() to execute "IBAR", clearing instruction hazards system-wide and ensuring the "break" instruction is visible to the fetch units of all cores. 3. Robustness: It properly manages memory write permissions (ROX/RW) for the kernel text segment during patching, ensuring compatibility with CONFIG_STRICT_KERNEL_RWX. Cc: <stable@vger.kernel.org> # 6.18+ Fixes: 6d4cc40fb5f5 ("LoongArch: Add kprobes support") Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e3ef9a28f558d1cbf0b42d6dcd16c60da557562b upstream.

On SMP systems, kprobe handlers would occasionally fail to execute on
certain CPU cores. The issue is hard to reproduce and typically occurs
randomly under high system load.

The root cause is a software-side instruction hazard. According to the
LoongArch Reference Manual, while the cache coherency is maintained by
hardware, software must explicitly use the "IBAR" instruction to ensure
the instruction fetch unit (IFU) observes the effects of recent stores.

The current arch_arm_kprobe() and arch_disarm_kprobe() only execute the
"IBAR" barrier (via flush_insn_slot -> local_flush_icache_range) on the
local CPU. This leaves a vulnerable window where remote CPU cores may
continue executing stale instructions from their pipelines or prefetch
buffers, as they have not executed an "IBAR" since the code modification.

Switch to larch_insn_text_copy() to fix this:
1. Synchronization: It uses stop_machine_cpuslocked() to synchronize all
   online CPUs, ensuring no CPU is executing the target code area during
   modification.
2. Visibility: By passing cpu_online_mask to stop_machine_cpuslocked(),
   the callback text_copy_cb() is executed on all online cores. Each CPU
   core invokes local_flush_icache_range() to execute "IBAR", clearing
   instruction hazards system-wide and ensuring the "break" instruction
   is visible to the fetch units of all cores.
3. Robustness: It properly manages memory write permissions (ROX/RW) for
   the kernel text segment during patching, ensuring compatibility with
   CONFIG_STRICT_KERNEL_RWX.

Cc: <stable@vger.kernel.org>  # 6.18+
Fixes: 6d4cc40fb5f5 ("LoongArch: Add kprobes support")
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: Show CPU vulnerabilites correctly 2026-05-07T04:11:47+00:00 Huacai Chen chenhuacai@loongson.cn 2026-04-22T07:45:12+00:00 988eff645be4e54dc01060f9660b1415d59d550a commit 37e57e8ad96cdec4a57b55fd10bef50f7370a954 upstream. Most LoongArch processors are vulnerable to Spectre-V1 Proof-of-Concept (PoC). And the generic mechanism, __user pointer sanitization, can be used as a mitigation. This means to use array_index_nospec() to prevent out of boundry access in syscall and other critical paths. Implement the arch-specific cpu_show_spectre_v1() to show CPU Spectre-V1 vulnerabilites correctly. Cc: stable@vger.kernel.org Link: https://cc-sw.com/chinese-loongarch-architecture-evaluation-part-3-of-3/ Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 37e57e8ad96cdec4a57b55fd10bef50f7370a954 upstream.

Most LoongArch processors are vulnerable to Spectre-V1 Proof-of-Concept
(PoC). And the generic mechanism, __user pointer sanitization, can be
used as a mitigation. This means to use array_index_nospec() to prevent
out of boundry access in syscall and other critical paths.

Implement the arch-specific cpu_show_spectre_v1() to show CPU Spectre-V1
vulnerabilites correctly.

Cc: stable@vger.kernel.org
Link: https://cc-sw.com/chinese-loongarch-architecture-evaluation-part-3-of-3/
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: Add spectre boundry for syscall dispatch table 2026-05-07T04:11:31+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2026-04-22T07:45:12+00:00 85cbf7fb568af5358aae61925c4e66b8f5e1439d commit 0c965d2784fbbd7f8e3b96d875c9cfdf7c00da3d upstream. The LoongArch syscall number is directly controlled by userspace, but does not have a array_index_nospec() boundry to prevent access past the syscall function pointer tables. Cc: stable@vger.kernel.org Assisted-by: gkh_clanker_2000 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 0c965d2784fbbd7f8e3b96d875c9cfdf7c00da3d upstream.

The LoongArch syscall number is directly controlled by userspace, but
does not have a array_index_nospec() boundry to prevent access past the
syscall function pointer tables.

Cc: stable@vger.kernel.org
Assisted-by: gkh_clanker_2000
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: vDSO: Emit GNU_EH_FRAME correctly 2026-04-02T11:23:24+00:00 Xi Ruoyao xry111@xry111.site 2026-03-26T06:29:09+00:00 53a27c09850be4f5fcb225bfcb19eab7202e6933 commit e4878c37f6679fdea91b27a0f4e60a871f0b7bad upstream. With -fno-asynchronous-unwind-tables and --no-eh-frame-hdr (the default of the linker), the GNU_EH_FRAME segment (specified by vdso.lds.S) is empty. This is not valid, as the current DWARF specification mandates the first byte of the EH frame to be the version number 1. It causes some unwinders to complain, for example the ClickHouse query profiler spams the log with messages: clickhouse-server[365854]: libunwind: unsupported .eh_frame_hdr version: 127 at 7ffffffb0000 Here "127" is just the byte located at the p_vaddr (0, i.e. the beginning of the vDSO) of the empty GNU_EH_FRAME segment. Cross- checking with /proc/365854/maps has also proven 7ffffffb0000 is the start of vDSO in the process VM image. In LoongArch the -fno-asynchronous-unwind-tables option seems just a MIPS legacy, and MIPS only uses this option to satisfy the MIPS-specific "genvdso" program, per the commit cfd75c2db17e ("MIPS: VDSO: Explicitly use -fno-asynchronous-unwind-tables"). IIRC it indicates some inherent limitation of the MIPS ELF ABI and has nothing to do with LoongArch. So we can simply flip it over to -fasynchronous-unwind-tables and pass --eh-frame-hdr for linking the vDSO, allowing the profilers to unwind the stack for statistics even if the sample point is taken when the PC is in the vDSO. However simply adjusting the options above would exploit an issue: when the libgcc unwinder saw the invalid GNU_EH_FRAME segment, it silently falled back to a machine-specific routine to match the code pattern of rt_sigreturn() and extract the registers saved in the sigframe if the code pattern is matched. As unwinding from signal handlers is vital for libgcc to support pthread cancellation etc., the fall-back routine had been silently keeping the LoongArch Linux systems functioning since Linux 5.19. But when we start to emit GNU_EH_FRAME with the correct format, fall-back routine will no longer be used and libgcc will fail to unwind the sigframe, and unwinding from signal handlers will no longer work, causing dozens of glibc test failures. To make it possible to unwind from signal handlers again, it's necessary to code the unwind info in __vdso_rt_sigreturn via .cfi_* directives. The offsets in the .cfi_* directives depend on the layout of struct sigframe, notably the offset of sigcontext in the sigframe. To use the offset in the assembly file, factor out struct sigframe into a header to allow asm-offsets.c to output the offset for assembly. To work around a long-term issue in the libgcc unwinder (the pc is unconditionally substracted by 1: doing so is technically incorrect for a signal frame), a nop instruction is included with the two real instructions in __vdso_rt_sigreturn in the same FDE PC range. The same hack has been used on x86 for a long time. Cc: stable@vger.kernel.org Fixes: c6b99bed6b8f ("LoongArch: Add VDSO and VSYSCALL support") Signed-off-by: Xi Ruoyao <xry111@xry111.site> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e4878c37f6679fdea91b27a0f4e60a871f0b7bad upstream.

With -fno-asynchronous-unwind-tables and --no-eh-frame-hdr (the default
of the linker), the GNU_EH_FRAME segment (specified by vdso.lds.S) is
empty.  This is not valid, as the current DWARF specification mandates
the first byte of the EH frame to be the version number 1.  It causes
some unwinders to complain, for example the ClickHouse query profiler
spams the log with messages:

    clickhouse-server[365854]: libunwind: unsupported .eh_frame_hdr
    version: 127 at 7ffffffb0000

Here "127" is just the byte located at the p_vaddr (0, i.e. the
beginning of the vDSO) of the empty GNU_EH_FRAME segment. Cross-
checking with /proc/365854/maps has also proven 7ffffffb0000 is the
start of vDSO in the process VM image.

In LoongArch the -fno-asynchronous-unwind-tables option seems just a
MIPS legacy, and MIPS only uses this option to satisfy the MIPS-specific
"genvdso" program, per the commit cfd75c2db17e ("MIPS: VDSO: Explicitly
use -fno-asynchronous-unwind-tables").  IIRC it indicates some inherent
limitation of the MIPS ELF ABI and has nothing to do with LoongArch.  So
we can simply flip it over to -fasynchronous-unwind-tables and pass
--eh-frame-hdr for linking the vDSO, allowing the profilers to unwind the
stack for statistics even if the sample point is taken when the PC is in
the vDSO.

However simply adjusting the options above would exploit an issue: when
the libgcc unwinder saw the invalid GNU_EH_FRAME segment, it silently
falled back to a machine-specific routine to match the code pattern of
rt_sigreturn() and extract the registers saved in the sigframe if the
code pattern is matched.  As unwinding from signal handlers is vital for
libgcc to support pthread cancellation etc., the fall-back routine had
been silently keeping the LoongArch Linux systems functioning since
Linux 5.19.  But when we start to emit GNU_EH_FRAME with the correct
format, fall-back routine will no longer be used and libgcc will fail
to unwind the sigframe, and unwinding from signal handlers will no
longer work, causing dozens of glibc test failures.  To make it possible
to unwind from signal handlers again, it's necessary to code the unwind
info in __vdso_rt_sigreturn via .cfi_* directives.

The offsets in the .cfi_* directives depend on the layout of struct
sigframe, notably the offset of sigcontext in the sigframe.  To use the
offset in the assembly file, factor out struct sigframe into a header to
allow asm-offsets.c to output the offset for assembly.

To work around a long-term issue in the libgcc unwinder (the pc is
unconditionally substracted by 1: doing so is technically incorrect for
a signal frame), a nop instruction is included with the two real
instructions in __vdso_rt_sigreturn in the same FDE PC range.  The same
hack has been used on x86 for a long time.

Cc: stable@vger.kernel.org
Fixes: c6b99bed6b8f ("LoongArch: Add VDSO and VSYSCALL support")
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: Fix missing NULL checks for kstrdup() 2026-04-02T11:23:24+00:00 Li Jun lijun01@kylinos.cn 2026-03-26T06:29:08+00:00 a1da957c25cf751a2dce8fb7777f82ccbac0cb3e commit 3a28daa9b7d7c2ddf2c722e9e95d7e0928bf0cd1 upstream. 1. Replace "of_find_node_by_path("/")" with "of_root" to avoid multiple calls to "of_node_put()". 2. Fix a potential kernel oops during early boot when memory allocation fails while parsing CPU model from device tree. Cc: stable@vger.kernel.org Signed-off-by: Li Jun <lijun01@kylinos.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3a28daa9b7d7c2ddf2c722e9e95d7e0928bf0cd1 upstream.

1. Replace "of_find_node_by_path("/")" with "of_root" to avoid multiple
calls to "of_node_put()".

2. Fix a potential kernel oops during early boot when memory allocation
fails while parsing CPU model from device tree.

Cc: stable@vger.kernel.org
Signed-off-by: Li Jun <lijun01@kylinos.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: Check return values for set_memory_{rw,rox} 2026-03-25T10:10:32+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2026-03-20T13:52:59+00:00 bea2848ba20e147f743aa96b92e5b90686cad92d [ Upstream commit 431ce839dad66d0d56fb604785452c6a57409f35 ] set_memory_rw() and set_memory_rox() may fail, so we should check the return values and return immediately in larch_insn_text_copy(). Cc: stable@vger.kernel.org Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> [ kept `stop_machine()` instead of `stop_machine_cpuslocked()` ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 431ce839dad66d0d56fb604785452c6a57409f35 ]

set_memory_rw() and set_memory_rox() may fail, so we should check the
return values and return immediately in larch_insn_text_copy().

Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
[ kept `stop_machine()` instead of `stop_machine_cpuslocked()` ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LoongArch: No need to flush icache if text copy failed 2026-03-25T10:10:31+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2026-03-16T02:36:01+00:00 8dd23bb5c6f5cb7c57917541338b7842996e448b commit d3b8491961207ac967795c34375890407fd51a45 upstream. If copy_to_kernel_nofault() failed, no need to flush icache and just return immediately. Cc: stable@vger.kernel.org Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d3b8491961207ac967795c34375890407fd51a45 upstream.

If copy_to_kernel_nofault() failed, no need to flush icache and just
return immediately.

Cc: stable@vger.kernel.org
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>