user/sven/linux.git/arch, branch v4.14.335

s390/vx: fix save/restore of fpu kernel context

2024-01-08T10:25:02Z

[ Upstream commit e6b2dab41888332bf83f592131e7ea07756770a4 ] The KERNEL_FPR mask only contains a flag for the first eight vector registers. However floating point registers overlay parts of the first sixteen vector registers. This could lead to vector register corruption if a kernel fpu context uses any of the vector registers 8 to 15 and is interrupted or calls a KERNEL_FPR context. If that context uses also vector registers 8 to 15, their contents will be corrupted on return. Luckily this is currently not a real bug, since the kernel has only one KERNEL_FPR user with s390_adjust_jiffies() and it is only using floating point registers 0 to 2. Fix this by using the correct bits for KERNEL_FPR. Fixes: 7f79695cc1b6 ("s390/fpu: improve kernel_fpu_[begin|end]") Signed-off-by: Heiko Carstens Reviewed-by: Hendrik Brueckner Signed-off-by: Alexander Gordeev Signed-off-by: Sasha Levin

ARM: OMAP2+: Fix null pointer dereference and memory leak in omap_soc_device_init

2024-01-08T10:25:02Z

[ Upstream commit c72b9c33ef9695ad7ce7a6eb39a9df8a01b70796 ] kasprintf() returns a pointer to dynamically allocated memory which can be NULL upon failure. When 'soc_dev_attr->family' is NULL,it'll trigger the null pointer dereference issue, such as in 'soc_info_show'. And when 'soc_device_register' fails, it's necessary to release 'soc_dev_attr->family' to avoid memory leaks. Fixes: 6770b2114325 ("ARM: OMAP2+: Export SoC information to userspace") Signed-off-by: Kunwu Chan Message-ID: <20231123145237.609442-1-chentao@kylinos.cn> Signed-off-by: Tony Lindgren Signed-off-by: Sasha Levin

powerpc/ftrace: Fix stack teardown in ftrace_no_trace

2023-12-20T14:32:39Z

commit 4b3338aaa74d7d4ec5b6734dc298f0db94ec83d2 upstream. Commit 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") added use of a new stack frame on ftrace entry to fix stack unwind. However, the commit missed updating the offset used while tearing down the ftrace stack when ftrace is disabled. Fix the same. In addition, the commit missed saving the correct stack pointer in pt_regs. Update the same. Fixes: 41a506ef71eb ("powerpc/ftrace: Create a dummy stackframe to fix stack unwind") Cc: stable@vger.kernel.org # v6.5+ Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20231130065947.2188860-1-naveen@kernel.org Signed-off-by: Greg Kroah-Hartman

powerpc/ftrace: Create a dummy stackframe to fix stack unwind

2023-12-20T14:32:39Z

commit 41a506ef71eb38d94fe133f565c87c3e06ccc072 upstream. With ppc64 -mprofile-kernel and ppc32 -pg, profiling instructions to call into ftrace are emitted right at function entry. The instruction sequence used is minimal to reduce overhead. Crucially, a stackframe is not created for the function being traced. This breaks stack unwinding since the function being traced does not have a stackframe for itself. As such, it never shows up in the backtrace: /sys/kernel/debug/tracing # echo 1 > /proc/sys/kernel/stack_tracer_enabled /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 4144 32 ftrace_call+0x4/0x44 1) 4112 432 get_page_from_freelist+0x26c/0x1ad0 2) 3680 496 __alloc_pages+0x290/0x1280 3) 3184 336 __folio_alloc+0x34/0x90 4) 2848 176 vma_alloc_folio+0xd8/0x540 5) 2672 272 __handle_mm_fault+0x700/0x1cc0 6) 2400 208 handle_mm_fault+0xf0/0x3f0 7) 2192 80 ___do_page_fault+0x3e4/0xbe0 8) 2112 160 do_page_fault+0x30/0xc0 9) 1952 256 data_access_common_virt+0x210/0x220 10) 1696 400 0xc00000000f16b100 11) 1296 384 load_elf_binary+0x804/0x1b80 12) 912 208 bprm_execve+0x2d8/0x7e0 13) 704 64 do_execveat_common+0x1d0/0x2f0 14) 640 160 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 Fix this by having ftrace create a dummy stackframe for the function being traced. With this, backtraces now capture the function being traced: /sys/kernel/debug/tracing # cat stack_trace Depth Size Location (17 entries) ----- ---- -------- 0) 3888 32 _raw_spin_trylock+0x8/0x70 1) 3856 576 get_page_from_freelist+0x26c/0x1ad0 2) 3280 64 __alloc_pages+0x290/0x1280 3) 3216 336 __folio_alloc+0x34/0x90 4) 2880 176 vma_alloc_folio+0xd8/0x540 5) 2704 416 __handle_mm_fault+0x700/0x1cc0 6) 2288 96 handle_mm_fault+0xf0/0x3f0 7) 2192 48 ___do_page_fault+0x3e4/0xbe0 8) 2144 192 do_page_fault+0x30/0xc0 9) 1952 608 data_access_common_virt+0x210/0x220 10) 1344 16 0xc0000000334bbb50 11) 1328 416 load_elf_binary+0x804/0x1b80 12) 912 64 bprm_execve+0x2d8/0x7e0 13) 848 176 do_execveat_common+0x1d0/0x2f0 14) 672 192 sys_execve+0x54/0x70 15) 480 64 system_call_exception+0x138/0x350 16) 416 416 system_call_common+0x160/0x2c4 This results in two additional stores in the ftrace entry code, but produces reliable backtraces. Fixes: 153086644fd1 ("powerpc/ftrace: Add support for -mprofile-kernel ftrace ABI") Cc: stable@vger.kernel.org Signed-off-by: Naveen N Rao Signed-off-by: Michael Ellerman Link: https://msgid.link/20230621051349.759567-1-naveen@kernel.org Signed-off-by: Greg Kroah-Hartman

KVM: s390/mm: Properly reset no-dat

2023-12-13T15:46:17Z

commit 27072b8e18a73ffeffb1c140939023915a35134b upstream. When the CMMA state needs to be reset, the no-dat bit also needs to be reset. Failure to do so could cause issues in the guest, since the guest expects the bit to be cleared after a reset. Cc: Reviewed-by: Nico Boehr Message-ID: <20231109123624.37314-1-imbrenda@linux.ibm.com> Signed-off-by: Claudio Imbrenda Signed-off-by: Greg Kroah-Hartman

powerpc: Don't clobber f0/vs0 during fp|altivec register save

2023-12-08T07:42:00Z

commit 5e1d824f9a283cbf90f25241b66d1f69adb3835b upstream. During floating point and vector save to thread data f0/vs0 are clobbered by the FPSCR/VSCR store routine. This has been obvserved to lead to userspace register corruption and application data corruption with io-uring. Fix it by restoring f0/vs0 after FPSCR/VSCR store has completed for all the FP, altivec, VMX register save paths. Tested under QEMU in kvm mode, running on a Talos II workstation with dual POWER9 DD2.2 CPUs. Additional detail (mpe): Typically save_fpu() is called from __giveup_fpu() which saves the FP regs and also *turns off FP* in the tasks MSR, meaning the kernel will reload the FP regs from the thread struct before letting the task use FP again. So in that case save_fpu() is free to clobber f0 because the FP regs no longer hold live values for the task. There is another case though, which is the path via: sys_clone() ... copy_process() dup_task_struct() arch_dup_task_struct() flush_all_to_thread() save_all() That path saves the FP regs but leaves them live. That's meant as an optimisation for a process that's using FP/VSX and then calls fork(), leaving the regs live means the parent process doesn't have to take a fault after the fork to get its FP regs back. The optimisation was added in commit 8792468da5e1 ("powerpc: Add the ability to save FPU without giving it up"). That path does clobber f0, but f0 is volatile across function calls, and typically programs reach copy_process() from userspace via a syscall wrapper function. So in normal usage f0 being clobbered across a syscall doesn't cause visible data corruption. But there is now a new path, because io-uring can call copy_process() via create_io_thread() from the signal handling path. That's OK if the signal is handled as part of syscall return, but it's not OK if the signal is handled due to some other interrupt. That path is: interrupt_return_srr_user() interrupt_exit_user_prepare() interrupt_exit_user_prepare_main() do_notify_resume() get_signal() task_work_run() create_worker_cb() create_io_worker() copy_process() dup_task_struct() arch_dup_task_struct() flush_all_to_thread() save_all() if (tsk->thread.regs->msr & MSR_FP) save_fpu() # f0 is clobbered and potentially live in userspace Note the above discussion applies equally to save_altivec(). Fixes: 8792468da5e1 ("powerpc: Add the ability to save FPU without giving it up") Cc: stable@vger.kernel.org # v4.6+ Closes: https://lore.kernel.org/all/480932026.45576726.1699374859845.JavaMail.zimbra@raptorengineeringinc.com/ Closes: https://lore.kernel.org/linuxppc-dev/480221078.47953493.1700206777956.JavaMail.zimbra@raptorengineeringinc.com/ Tested-by: Timothy Pearson Tested-by: Jens Axboe Signed-off-by: Timothy Pearson [mpe: Reword change log to describe exact path of corruption & other minor tweaks] Signed-off-by: Michael Ellerman Link: https://msgid.link/1921539696.48534988.1700407082933.JavaMail.zimbra@raptorengineeringinc.com Signed-off-by: Greg Kroah-Hartman

arm/xen: fix xen_vcpu_info allocation alignment

2023-12-08T07:41:59Z

[ Upstream commit 7bf9a6b46549852a37e6d07e52c601c3c706b562 ] xen_vcpu_info is a percpu area than needs to be mapped by Xen. Currently, it could cross a page boundary resulting in Xen being unable to map it: [ 0.567318] kernel BUG at arch/arm64/xen/../../arm/xen/enlighten.c:164! [ 0.574002] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP Fix the issue by using __alloc_percpu and requesting alignment for the memory allocation. Signed-off-by: Stefano Stabellini Link: https://lore.kernel.org/r/alpine.DEB.2.22.394.2311221501340.2053963@ubuntu-linux-20-04-desktop Fixes: 24d5373dda7c ("arm/xen: Use alloc_percpu rather than __alloc_percpu") Reviewed-by: Juergen Gross Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin

parisc/pgtable: Do not drop upper 5 address bits of physical address

2023-11-28T16:45:45Z

commit 166b0110d1ee53290bd11618df6e3991c117495a upstream. When calculating the pfn for the iitlbt/idtlbt instruction, do not drop the upper 5 address bits. This doesn't seem to have an effect on physical hardware which uses less physical address bits, but in qemu the missing bits are visible. Signed-off-by: Helge Deller Cc: Signed-off-by: Greg Kroah-Hartman

parisc: Prevent booting 64-bit kernels on PA1.x machines

2023-11-28T16:45:45Z

commit a406b8b424fa01f244c1aab02ba186258448c36b upstream. Bail out early with error message when trying to boot a 64-bit kernel on 32-bit machines. This fixes the previous commit to include the check for true 64-bit kernels as well. Signed-off-by: Helge Deller Fixes: 591d2108f3abc ("parisc: Add runtime check to prevent PA2.0 kernels on PA1.x machines") Cc: # v6.0+ Signed-off-by: Greg Kroah-Hartman

KVM: x86: Ignore MSR_AMD64_TW_CFG access

2023-11-28T16:45:44Z

commit 2770d4722036d6bd24bcb78e9cd7f6e572077d03 upstream. Hyper-V enabled Windows Server 2022 KVM VM cannot be started on Zen1 Ryzen since it crashes at boot with SYSTEM_THREAD_EXCEPTION_NOT_HANDLED + STATUS_PRIVILEGED_INSTRUCTION (in other words, because of an unexpected #GP in the guest kernel). This is because Windows tries to set bit 8 in MSR_AMD64_TW_CFG and can't handle receiving a #GP when doing so. Give this MSR the same treatment that commit 2e32b7190641 ("x86, kvm: Add MSR_AMD64_BU_CFG2 to the list of ignored MSRs") gave MSR_AMD64_BU_CFG2 under justification that this MSR is baremetal-relevant only. Although apparently it was then needed for Linux guests, not Windows as in this case. With this change, the aforementioned guest setup is able to finish booting successfully. This issue can be reproduced either on a Summit Ridge Ryzen (with just "-cpu host") or on a Naples EPYC (with "-cpu host,stepping=1" since EPYC is ordinarily stepping 2). Alternatively, userspace could solve the problem by using MSR filters, but forcing every userspace to define a filter isn't very friendly and doesn't add much, if any, value. The only potential hiccup is if one of these "baremetal-only" MSRs ever requires actual emulation and/or has F/M/S specific behavior. But if that happens, then KVM can still punt *that* handling to userspace since userspace MSR filters "win" over KVM's default handling. Signed-off-by: Maciej S. Szmigiero Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/1ce85d9c7c9e9632393816cf19c902e0a3f411f1.1697731406.git.maciej.szmigiero@oracle.com [sean: call out MSR filtering alternative] Signed-off-by: Sean Christopherson Signed-off-by: Greg Kroah-Hartman