kernel/linux.git/arch, branch v6.18.22

s390/cpum_sf: Cap sampling rate to prevent lsctl exception

2026-04-11T12:26:45+00:00

commit 57ad0d4a00f5d3e80f33ba2da8d560c73d83dc22 upstream. commit fcc43a7e294f ("s390/configs: Set HZ=1000") changed the interrupt frequency of the system. On machines with heavy load and many perf event overflows, this might lead to an exception. Dmesg displays these entries: [112.242542] cpum_sf: Loading sampling controls failed: op 1 err -22 One line per CPU online. The root cause is the CPU Measurement sampling facility overflow adjustment. Whenever an overflow (too much samples per tick) occurs, the sampling rate is adjusted and increased. This was done without observing the maximum sampling rate limit. When the current sampling interval is higher than the maximum sampling rate limit, the lsctl instruction raises an exception. The error messages is the result of such an exception. Observe the upper limit when the new sampling rate is recalculated. Cc: stable@vger.kernel.org Fixes: 39d4a501a9ef ("s390/cpum_sf: Adjust sampling interval to avoid hitting sample limits") Signed-off-by: Thomas Richter Reviewed-by: Sumanth Korikkar Reviewed-by: Hendrik Brueckner Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman

x86/kexec: Disable KCOV instrumentation after load_segments()

2026-04-11T12:26:36+00:00

commit 917e3ad3321e75ca0223d5ccf26ceda116aa51e1 upstream. The load_segments() function changes segment registers, invalidating GS base (which KCOV relies on for per-cpu data). When CONFIG_KCOV is enabled, any subsequent instrumented C code call (e.g. native_gdt_invalidate()) begins crashing the kernel in an endless loop. To reproduce the problem, it's sufficient to do kexec on a KCOV-instrumented kernel: $ kexec -l /boot/otherKernel $ kexec -e The real-world context for this problem is enabling crash dump collection in syzkaller. For this, the tool loads a panic kernel before fuzzing and then calls makedumpfile after the panic. This workflow requires both CONFIG_KEXEC and CONFIG_KCOV to be enabled simultaneously. Adding safeguards directly to the KCOV fast-path (__sanitizer_cov_trace_pc()) is also undesirable as it would introduce an extra performance overhead. Disabling instrumentation for the individual functions would be too fragile, so disable KCOV instrumentation for the entire machine_kexec_64.c and physaddr.c. If coverage-guided fuzzing ever needs these components in the future, other approaches should be considered. The problem is not relevant for 32 bit kernels as CONFIG_KCOV is not supported there. [ bp: Space out comment for better readability. ] Fixes: 0d345996e4cb ("x86/kernel: increase kcov coverage under arch/x86/kernel folder") Signed-off-by: Aleksandr Nogikh Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Dmitry Vyukov Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260325154825.551191-1-nogikh@google.com Signed-off-by: Greg Kroah-Hartman

mips: mm: Allocate tlb_vpn array atomically

2026-04-11T12:26:35+00:00

commit 01cc50ea5167bb14117257ec084637abe9e5f691 upstream. Found by DEBUG_ATOMIC_SLEEP: BUG: sleeping function called from invalid context at /include/linux/sched/mm.h:306 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/1 preempt_count: 1, expected: 0 RCU nest depth: 0, expected: 0 no locks held by swapper/1/0. irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [] copy_process+0x75c/0x1b68 softirqs last enabled at (0): [] copy_process+0x75c/0x1b68 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.6.119-d79e757675ec-fct #1 Stack : 800000000290bad8 0000000000000000 0000000000000008 800000000290bae8 800000000290bae8 800000000290bc78 0000000000000000 0000000000000000 ffffffff80c80000 0000000000000001 ffffffff80d8dee8 ffffffff810d09c0 784bb2a7ec10647d 0000000000000010 ffffffff80a6fd60 8000000001d8a9c0 0000000000000000 0000000000000000 ffffffff80d90000 0000000000000000 ffffffff80c9e0e8 0000000007ffffff 0000000000000cc0 0000000000000400 ffffffffffffffff 0000000000000001 0000000000000002 ffffffffc0149ed8 fffffffffffffffe 8000000002908000 800000000290bae0 ffffffff80a81b74 ffffffff80129fb0 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 ffffffff80129fd0 0000000000000000 ... Call Trace: [] show_stack+0x60/0x158 [] dump_stack_lvl+0x88/0xbc [] __might_resched+0x268/0x288 [] __kmem_cache_alloc_node+0x2e0/0x330 [] __kmalloc+0x58/0xd0 [] r4k_tlb_uniquify+0x7c/0x428 [] tlb_init+0x7c/0x110 [] per_cpu_trap_init+0x16c/0x1d0 [] start_secondary+0x28/0x128 Fixes: 231ac951faba ("MIPS: mm: kmalloc tlb_vpn array to avoid stack overflow") Signed-off-by: Stefan Wiehler Cc: stable@vger.kernel.org Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

MIPS: Fix the GCC version check for `__multi3' workaround

2026-04-11T12:26:35+00:00

commit ec8bf18814915460d9c617b556bf024efef26613 upstream. It was only GCC 10 that fixed a MIPS64r6 code generation issue with a `__multi3' libcall inefficiently produced to perform 64-bit widening multiplication while suitable machine instructions exist to do such a calculation. The fix went in with GCC commit 48b2123f6336 ("re PR target/82981 (unnecessary __multi3 call for mips64r6 linux kernel)"). Adjust our code accordingly, removing build failures such as: mips64-linux-ld: lib/math/div64.o: in function `mul_u64_add_u64_div_u64': div64.c:(.text+0x84): undefined reference to `__multi3' with the GCC versions affected. Fixes: ebabcf17bcd7 ("MIPS: Implement __multi3 for GCC7 MIPS64r6 builds") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202601140146.hMLODc6v-lkp@intel.com/ Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v4.15+ Reviewed-by: David Laight Signed-off-by: Greg Kroah-Hartman

MIPS: SiByte: Bring back cache initialisation

2026-04-11T12:26:35+00:00

commit d62cf1511743526f530a4c169424e50c757f5a5e upstream. Bring back cache initialisation for Broadcom SiByte SB1 cores, which has been removed causing the kernel to hang at bootstrap right after: Dentry cache hash table entries: 524288 (order: 8, 4194304 bytes, linear) Inode-cache hash table entries: 262144 (order: 7, 2097152 bytes, linear) The cause of the problem is R4k cache handlers are also used by Broadcom SiByte SB1 cores, however with a different cache error exception handler and therefore not using CPU_R4K_CACHE_TLB: obj-$(CONFIG_CPU_R4K_CACHE_TLB) += c-r4k.o cex-gen.o tlb-r4k.o obj-$(CONFIG_CPU_SB1) += c-r4k.o cerr-sb1.o cex-sb1.o tlb-r4k.o (from arch/mips/mm/Makefile). Fixes: bbe4f634f48c ("mips: fix r3k_cache_init build regression") Signed-off-by: Maciej W. Rozycki Cc: stable@vger.kernel.org # v6.8+ Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman

riscv: Reset pmm when PR_TAGGED_ADDR_ENABLE is not set

2026-04-11T12:26:33+00:00

[ Upstream commit 3033b2b1e3949274f33a140e2a97571b5a307298 ] In set_tagged_addr_ctrl(), when PR_TAGGED_ADDR_ENABLE is not set, pmlen is correctly set to 0, but it forgets to reset pmm. This results in the CPU pmm state not corresponding to the software pmlen state. Fix this by resetting pmm along with pmlen. Fixes: 2e1743085887 ("riscv: Add support for the tagged address ABI") Signed-off-by: Zishun Yi Reviewed-by: Samuel Holland Link: https://patch.msgid.link/20260322160022.21908-1-vulab@iscas.ac.cn Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

riscv: kgdb: fix several debug register assignment bugs

2026-04-11T12:26:32+00:00

[ Upstream commit 834911eb8eef2501485d819b4eabebadc25c3497 ] Fix several bugs in the RISC-V kgdb implementation: - The element of dbg_reg_def[] that is supposed to pertain to the S1 register embeds instead the struct pt_regs offset of the A1 register. Fix this to use the S1 register offset in struct pt_regs. - The sleeping_thread_to_gdb_regs() function copies the value of the S10 register into the gdb_regs[] array element meant for the S9 register, and copies the value of the S11 register into the array element meant for the S10 register. It also neglects to copy the value of the S11 register. Fix all of these issues. Fixes: fe89bd2be8667 ("riscv: Add KGDB support") Cc: Vincent Chen Link: https://patch.msgid.link/fde376f8-bcfd-bfe4-e467-07d8f7608d05@kernel.org Signed-off-by: Paul Walmsley Signed-off-by: Sasha Levin

perf/x86: Fix potential bad container_of in intel_pmu_hw_config

2026-04-11T12:26:32+00:00

[ Upstream commit dbde07f06226438cd2cf1179745fa1bec5d8914a ] Auto counter reload may have a group of events with software events present within it. The software event PMU isn't the x86_hybrid_pmu and a container_of operation in intel_pmu_set_acr_caused_constr (via the hybrid helper) could cause out of bound memory reads. Avoid this by guarding the call to intel_pmu_set_acr_caused_constr with an is_x86_event check. Fixes: ec980e4facef ("perf/x86/intel: Support auto counter reload") Signed-off-by: Ian Rogers Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Thomas Falcon Link: https://patch.msgid.link/20260312194305.1834035-1-irogers@google.com Signed-off-by: Sasha Levin

mips: ralink: update CPU clock index

2026-04-11T12:26:32+00:00

[ Upstream commit 43985a62bab9d35e5e9af41118ce2f44c01b97d2 ] Update CPU clock index to match the clock driver changes. Fixes: d34db686a3d7 ("clk: ralink: mtmips: fix clocks probe order in oldest ralink SoCs") Signed-off-by: Mieczyslaw Nalewaj Signed-off-by: Shiji Yang Reviewed-by: Sergio Paracuellos Signed-off-by: Thomas Bogendoerfer Signed-off-by: Sasha Levin

arm64/scs: Fix handling of advance_loc4

2026-04-11T12:26:16+00:00

[ Upstream commit d499e9627d70b1269020d59b95ed3e18bee6b8cd ] DW_CFA_advance_loc4 is defined but no handler is implemented. Its CFA opcode defaults to EDYNSCS_INVALID_CFA_OPCODE triggering an error which wrongfully prevents modules from loading. Link: https://bugs.gentoo.org/971060 Signed-off-by: Pepper Gray Signed-off-by: Will Deacon Signed-off-by: Sasha Levin