BMC/Intel-BMC/linux.git/arch, branch v5.4.43

x86/unwind/orc: Fix unwind_get_return_address_ptr() for inactive tasks

2020-05-27T15:46:50+00:00

commit 187b96db5ca79423618dfa29a05c438c34f9e1f0 upstream. Normally, show_trace_log_lvl() scans the stack, looking for text addresses to print. In parallel, it unwinds the stack with unwind_next_frame(). If the stack address matches the pointer returned by unwind_get_return_address_ptr() for the current frame, the text address is printed normally without a question mark. Otherwise it's considered a breadcrumb (potentially from a previous call path) and it's printed with a question mark to indicate that the address is unreliable and typically can be ignored. Since the following commit: f1d9a2abff66 ("x86/unwind/orc: Don't skip the first frame for inactive tasks") ... for inactive tasks, show_trace_log_lvl() prints *only* unreliable addresses (prepended with '?'). That happens because, for the first frame of an inactive task, unwind_get_return_address_ptr() returns the wrong return address pointer: one word *below* the task stack pointer. show_trace_log_lvl() starts scanning at the stack pointer itself, so it never finds the first 'reliable' address, causing only guesses to being printed. The first frame of an inactive task isn't a normal stack frame. It's actually just an instance of 'struct inactive_task_frame' which is left behind by __switch_to_asm(). Now that this inactive frame is actually exposed to callers, fix unwind_get_return_address_ptr() to interpret it properly. Fixes: f1d9a2abff66 ("x86/unwind/orc: Don't skip the first frame for inactive tasks") Reported-by: Tetsuo Handa Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20200522135435.vbxs7umku5pyrdbk@treble Signed-off-by: Greg Kroah-Hartman

s390/kexec_file: fix initrd location for kdump kernel

2020-05-27T15:46:49+00:00

commit 70b690547d5ea1a3d135a4cc39cd1e08246d0c3a upstream. initrd_start must not point at the location the initrd is loaded into the crashkernel memory but at the location it will be after the crashkernel memory is swapped with the memory at 0. Fixes: ee337f5469fd ("s390/kexec_file: Add crash support to image loader") Reported-by: Lianbo Jiang Signed-off-by: Philipp Rudo Tested-by: Lianbo Jiang Link: https://lore.kernel.org/r/20200512193956.15ae3f23@laptop2-ibm.local Signed-off-by: Christian Borntraeger Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/kaslr: add support for R_390_JMP_SLOT relocation type

2020-05-27T15:46:47+00:00

commit 4c1cbcbd6c56c79de2c07159be4f55386bb0bef2 upstream. With certain kernel configurations, the R_390_JMP_SLOT relocation type might be generated, which is not expected by the KASLR relocation code, and the kernel stops with the message "Unknown relocation type". This was found with a zfcpdump kernel config, where CONFIG_MODULES=n and CONFIG_VFIO=n. In that case, symbol_get() is used on undefined __weak symbols in virt/kvm/vfio.c, which results in the generation of R_390_JMP_SLOT relocation types. Fix this by handling R_390_JMP_SLOT similar to R_390_GLOB_DAT. Fixes: 805bc0bc238f ("s390/kernel: build a relocatable kernel") Cc: # v5.2+ Signed-off-by: Gerald Schaefer Reviewed-by: Philipp Rudo Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

s390/pci: Fix s390_mmio_read/write with MIO

2020-05-27T15:46:47+00:00

commit f058599e22d59e594e5aae1dc10560568d8f4a8b upstream. The s390_mmio_read/write syscalls are currently broken when running with MIO. The new pcistb_mio/pcstg_mio/pcilg_mio instructions are executed similiarly to normal load/store instructions and do address translation in the current address space. That means inside the kernel they are aware of mappings into kernel address space while outside the kernel they use user space mappings (usually created through mmap'ing a PCI device file). Now when existing user space applications use the s390_pci_mmio_write and s390_pci_mmio_read syscalls, they pass I/O addresses that are mapped into user space so as to be usable with the new instructions without needing a syscall. Accessing these addresses with the old instructions as done currently leads to a kernel panic. Also, for such a user space mapping there may not exist an equivalent kernel space mapping which means we can't just use the new instructions in kernel space. Instead of replicating user mappings in the kernel which then might collide with other mappings, we can conceptually execute the new instructions as if executed by the user space application using the secondary address space. This even allows us to directly store to the user pointer without the need for copy_to/from_user(). Cc: stable@vger.kernel.org Fixes: 71ba41c9b1d9 ("s390/pci: provide support for MIO instructions") Signed-off-by: Niklas Schnelle Reviewed-by: Sven Schnelle Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Disable STRICT_KERNEL_RWX

2020-05-27T15:46:44+00:00

[ Upstream commit 8659a0e0efdd975c73355dbc033f79ba3b31e82c ] Several strange crashes have been eventually traced back to STRICT_KERNEL_RWX and its interaction with code patching. Various paths in our ftrace, kprobes and other patching code need to be hardened against patching failures, otherwise we can end up running with partially/incorrectly patched ftrace paths, kprobes or jump labels, which can then cause strange crashes. Although fixes for those are in development, they're not -rc material. There also seem to be problems with the underlying strict RWX logic, which needs further debugging. So for now disable STRICT_KERNEL_RWX on 64-bit to prevent people from enabling the option and tripping over the bugs. Fixes: 1e0fc9d1eb2b ("powerpc/Kconfig: Enable STRICT_KERNEL_RWX for some configs") Cc: stable@vger.kernel.org # v4.13+ Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200520133605.972649-1-mpe@ellerman.id.au Signed-off-by: Sasha Levin

powerpc: Remove STRICT_KERNEL_RWX incompatibility with RELOCATABLE

2020-05-27T15:46:44+00:00

[ Upstream commit c55d7b5e64265fdca45c85b639013e770bde2d0e ] I have tested this with the Radix MMU and everything seems to work, and the previous patch for Hash seems to fix everything too. STRICT_KERNEL_RWX should still be disabled by default for now. Please test STRICT_KERNEL_RWX + RELOCATABLE! Signed-off-by: Russell Currey Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191224064126.183670-2-ruscur@russell.cc Signed-off-by: Sasha Levin

arm64: Fix PTRACE_SYSEMU semantics

2020-05-27T15:46:40+00:00

commit 1cf6022bd9161081215028203919c33fcfa6debb upstream. Quoth the man page: ``` If the tracee was restarted by PTRACE_SYSCALL or PTRACE_SYSEMU, the tracee enters syscall-enter-stop just prior to entering any system call (which will not be executed if the restart was using PTRACE_SYSEMU, regardless of any change made to registers at this point or how the tracee is restarted after this stop). ``` The parenthetical comment is currently true on x86 and powerpc, but not currently true on arm64. arm64 re-checks the _TIF_SYSCALL_EMU flag after the syscall entry ptrace stop. However, at this point, it reflects which method was used to re-start the syscall at the entry stop, rather than the method that was used to reach it. Fix that by recording the original flag before performing the ptrace stop, bringing the behavior in line with documentation and x86/powerpc. Fixes: f086f67485c5 ("arm64: ptrace: add support for syscall emulation") Cc: # 5.3.x- Signed-off-by: Keno Fischer Acked-by: Will Deacon Tested-by: Sudeep Holla Tested-by: Bin Lu [catalin.marinas@arm.com: moved 'flags' bit masking] [catalin.marinas@arm.com: changed 'flags' type to unsigned long] Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman

KVM: x86: Fix pkru save/restore when guest CR4.PKE=0, move it to x86.c

2020-05-27T15:46:39+00:00

commit 37486135d3a7b03acc7755b63627a130437f066a upstream. Though rdpkru and wrpkru are contingent upon CR4.PKE, the PKRU resource isn't. It can be read with XSAVE and written with XRSTOR. So, if we don't set the guest PKRU value here(kvm_load_guest_xsave_state), the guest can read the host value. In case of kvm_load_host_xsave_state, guest with CR4.PKE clear could potentially use XRSTOR to change the host PKRU value. While at it, move pkru state save/restore to common code and the host_pkru field to kvm_vcpu_arch. This will let SVM support protection keys. Cc: stable@vger.kernel.org Reported-by: Jim Mattson Signed-off-by: Babu Moger Message-Id: <158932794619.44260.14508381096663848853.stgit@naples-babu.amd.com> Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman

ARM: futex: Address build warning

2020-05-27T15:46:36+00:00

[ Upstream commit 8101b5a1531f3390b3a69fa7934c70a8fd6566ad ] Stephen reported the following build warning on a ARM multi_v7_defconfig build with GCC 9.2.1: kernel/futex.c: In function 'do_futex': kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] 1676 | return oldval == cmparg; | ~~~~~~~^~~~~~~~~ kernel/futex.c:1652:6: note: 'oldval' was declared here 1652 | int oldval, ret; | ^~~~~~ introduced by commit a08971e9488d ("futex: arch_futex_atomic_op_inuser() calling conventions change"). While that change should not make any difference it confuses GCC which fails to work out that oldval is not referenced when the return value is not zero. GCC fails to properly analyze arch_futex_atomic_op_inuser(). It's not the early return, the issue is with the assembly macros. GCC fails to detect that those either set 'ret' to 0 and set oldval or set 'ret' to -EFAULT which makes oldval uninteresting. The store to the callsite supplied oldval pointer is conditional on ret == 0. The straight forward way to solve this is to make the store unconditional. Aside of addressing the build warning this makes sense anyway because it removes the conditional from the fastpath. In the error case the stored value is uninteresting and the extra store does not matter at all. Reported-by: Stephen Rothwell Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/87pncao2ph.fsf@nanos.tec.linutronix.de Signed-off-by: Sasha Levin

x86/apic: Move TSC deadline timer debug printk

2020-05-27T15:46:33+00:00

[ Upstream commit c84cb3735fd53c91101ccdb191f2e3331a9262cb ] Leon reported that the printk_once() in __setup_APIC_LVTT() triggers a lockdep splat due to a lock order violation between hrtimer_base::lock and console_sem, when the 'once' condition is reset via /sys/kernel/debug/clear_warn_once after boot. The initial printk cannot trigger this because that happens during boot when the local APIC timer is set up on the boot CPU. Prevent it by moving the printk to a place which is guaranteed to be only called once during boot. Mark the deadline timer check related functions and data __init while at it. Reported-by: Leon Romanovsky Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/87y2qhoshi.fsf@nanos.tec.linutronix.de Signed-off-by: Sasha Levin