From 060ea84a484e852b52b938f234bf9b5503a6c910 Mon Sep 17 00:00:00 2001 From: Chunyan Zhang Date: Mon, 27 Oct 2025 11:40:43 -0600 Subject: [PATCH 1/8] riscv: stacktrace: Disable KASAN checks for non-current tasks Unwinding the stack of a task other than current, KASAN would report "BUG: KASAN: out-of-bounds in walk_stackframe+0x41c/0x460" There is a same issue on x86 and has been resolved by the commit 84936118bdf3 ("x86/unwind: Disable KASAN checks for non-current tasks") The solution could be applied to RISC-V too. This patch also can solve the issue: https://seclists.org/oss-sec/2025/q4/23 Fixes: 5d8544e2d007 ("RISC-V: Generic library routines and assembly") Co-developed-by: Jiakai Xu Signed-off-by: Jiakai Xu Signed-off-by: Chunyan Zhang Link: https://lore.kernel.org/r/20251022072608.743484-1-zhangchunyan@iscas.ac.cn [pjw@kernel.org: clean up checkpatch issues] Signed-off-by: Paul Walmsley --- arch/riscv/kernel/stacktrace.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 3fe9e6edef8f..b41b6255751c 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -16,6 +16,22 @@ #ifdef CONFIG_FRAME_POINTER +/* + * This disables KASAN checking when reading a value from another task's stack, + * since the other task could be running on another CPU and could have poisoned + * the stack in the meantime. + */ +#define READ_ONCE_TASK_STACK(task, x) \ +({ \ + unsigned long val; \ + unsigned long addr = x; \ + if ((task) == current) \ + val = READ_ONCE(addr); \ + else \ + val = READ_ONCE_NOCHECK(addr); \ + val; \ +}) + extern asmlinkage void handle_exception(void); extern unsigned long ret_from_exception_end; @@ -69,8 +85,9 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, fp = frame->ra; pc = regs->ra; } else { - fp = frame->fp; - pc = ftrace_graph_ret_addr(current, &graph_idx, frame->ra, + fp = READ_ONCE_TASK_STACK(task, frame->fp); + pc = READ_ONCE_TASK_STACK(task, frame->ra); + pc = ftrace_graph_ret_addr(current, &graph_idx, pc, &frame->ra); if (pc >= (unsigned long)handle_exception && pc < (unsigned long)&ret_from_exception_end) { From a74f038fa50e0d33b740f44f862fe856f16de6a8 Mon Sep 17 00:00:00 2001 From: Josephine Pfeiffer Date: Mon, 27 Oct 2025 11:40:43 -0600 Subject: [PATCH 2/8] riscv: ptdump: use seq_puts() in pt_dump_seq_puts() macro The pt_dump_seq_puts() macro incorrectly uses seq_printf() instead of seq_puts(). This is both a performance issue and conceptually wrong, as the macro name suggests plain string output (puts) but the implementation uses formatted output (printf). The macro is used in ptdump.c:301 to output a newline character. Using seq_printf() adds unnecessary overhead for format string parsing when outputting this constant string. This bug was introduced in commit 59c4da8640cc ("riscv: Add support to dump the kernel page tables") in 2020, which copied the implementation pattern from other architectures that had the same bug. Fixes: 59c4da8640cc ("riscv: Add support to dump the kernel page tables") Signed-off-by: Josephine Pfeiffer Link: https://lore.kernel.org/r/20251018170451.3355496-1-hi@josie.lol Signed-off-by: Paul Walmsley --- arch/riscv/mm/ptdump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/mm/ptdump.c b/arch/riscv/mm/ptdump.c index 3b51690cc876..34299c2b231f 100644 --- a/arch/riscv/mm/ptdump.c +++ b/arch/riscv/mm/ptdump.c @@ -21,7 +21,7 @@ #define pt_dump_seq_puts(m, fmt) \ ({ \ if (m) \ - seq_printf(m, fmt); \ + seq_puts(m, fmt); \ }) /* From c42458fcf54b3d0bc2ac06667c98dceb43831889 Mon Sep 17 00:00:00 2001 From: Miaoqian Lin Date: Mon, 27 Oct 2025 11:40:44 -0600 Subject: [PATCH 3/8] riscv: Fix memory leak in module_frob_arch_sections() The current code directly overwrites the scratch pointer with the return value of kvrealloc(). If kvrealloc() fails and returns NULL, the original buffer becomes unreachable, causing a memory leak. Fix this by using a temporary variable to store kvrealloc()'s return value and only update the scratch pointer on success. Found via static anlaysis and this is similar to commit 42378a9ca553 ("bpf, verifier: Fix memory leak in array reallocation for stack state") Fixes: be17c0df6795 ("riscv: module: Optimize PLT/GOT entry counting") Cc: stable@vger.kernel.org Signed-off-by: Miaoqian Lin Link: https://lore.kernel.org/r/20251026091912.39727-1-linmq006@gmail.com Signed-off-by: Paul Walmsley --- arch/riscv/kernel/module-sections.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/module-sections.c b/arch/riscv/kernel/module-sections.c index 75551ac6504c..1675cbad8619 100644 --- a/arch/riscv/kernel/module-sections.c +++ b/arch/riscv/kernel/module-sections.c @@ -119,6 +119,7 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, unsigned int num_plts = 0; unsigned int num_gots = 0; Elf_Rela *scratch = NULL; + Elf_Rela *new_scratch; size_t scratch_size = 0; int i; @@ -168,9 +169,12 @@ int module_frob_arch_sections(Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, scratch_size_needed = (num_scratch_relas + num_relas) * sizeof(*scratch); if (scratch_size_needed > scratch_size) { scratch_size = scratch_size_needed; - scratch = kvrealloc(scratch, scratch_size, GFP_KERNEL); - if (!scratch) + new_scratch = kvrealloc(scratch, scratch_size, GFP_KERNEL); + if (!new_scratch) { + kvfree(scratch); return -ENOMEM; + } + scratch = new_scratch; } for (size_t j = 0; j < num_relas; j++) From 217660325580d51c350726159703b2fcec2b95e3 Mon Sep 17 00:00:00 2001 From: Vivian Wang Date: Mon, 20 Oct 2025 20:23:55 +0800 Subject: [PATCH 4/8] riscv: tests: Rename kprobes_test_riscv to kprobes_riscv According to Documentation/dev-tools/kunit/style.rst a KUnit test suite normally should not have "test" in the name. Rename it to follow the style guide. Signed-off-by: Vivian Wang Tested-by: Inochi Amaoto Reviewed-by: Nam Cao Link: https://lore.kernel.org/r/20251020-riscv-kunit-kconfig-fix-6-18-v1-1-d773b5d5ce48@iscas.ac.cn Signed-off-by: Paul Walmsley --- arch/riscv/kernel/tests/kprobes/test-kprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/kernel/tests/kprobes/test-kprobes.c b/arch/riscv/kernel/tests/kprobes/test-kprobes.c index 6f6cdfbf5a95..0716c88bcec7 100644 --- a/arch/riscv/kernel/tests/kprobes/test-kprobes.c +++ b/arch/riscv/kernel/tests/kprobes/test-kprobes.c @@ -49,7 +49,7 @@ static struct kunit_case kprobes_testcases[] = { }; static struct kunit_suite kprobes_test_suite = { - .name = "kprobes_test_riscv", + .name = "kprobes_riscv", .test_cases = kprobes_testcases, }; From 5fada1605733a427feff45147cef9455ce29620f Mon Sep 17 00:00:00 2001 From: Vivian Wang Date: Mon, 20 Oct 2025 20:23:56 +0800 Subject: [PATCH 5/8] riscv: tests: Make RISCV_KPROBES_KUNIT tristate This disallows KUNIT=m and RISCV_KPROBES_KUNIT=y, which produces these relocs_check.sh warnings when RELOCATABLE=y: WARNING: 3 bad relocations ffffffff81e24118 R_RISCV_64 kunit_unary_assert_format ffffffff81e24a60 R_RISCV_64 kunit_binary_assert_format ffffffff81e269d0 R_RISCV_JUMP_SLOT __kunit_do_failed_assertion This fixes allmodconfig build. Reported-by: Inochi Amaoto Fixes: f2fab612824f ("riscv: Add kprobes KUnit test") Signed-off-by: Vivian Wang Tested-by: Inochi Amaoto Reviewed-by: Nam Cao Link: https://lore.kernel.org/r/20251020-riscv-kunit-kconfig-fix-6-18-v1-2-d773b5d5ce48@iscas.ac.cn Signed-off-by: Paul Walmsley --- arch/riscv/kernel/tests/Kconfig.debug | 2 +- arch/riscv/kernel/tests/kprobes/Makefile | 4 +++- arch/riscv/kernel/tests/kprobes/test-kprobes.c | 3 +++ 3 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/tests/Kconfig.debug b/arch/riscv/kernel/tests/Kconfig.debug index 5db4df44279e..40f8dafffa0a 100644 --- a/arch/riscv/kernel/tests/Kconfig.debug +++ b/arch/riscv/kernel/tests/Kconfig.debug @@ -31,7 +31,7 @@ config RISCV_MODULE_LINKING_KUNIT If unsure, say N. config RISCV_KPROBES_KUNIT - bool "KUnit test for riscv kprobes" if !KUNIT_ALL_TESTS + tristate "KUnit test for riscv kprobes" if !KUNIT_ALL_TESTS depends on KUNIT depends on KPROBES default KUNIT_ALL_TESTS diff --git a/arch/riscv/kernel/tests/kprobes/Makefile b/arch/riscv/kernel/tests/kprobes/Makefile index 4cb6c66a98e8..df7256f62313 100644 --- a/arch/riscv/kernel/tests/kprobes/Makefile +++ b/arch/riscv/kernel/tests/kprobes/Makefile @@ -1 +1,3 @@ -obj-y += test-kprobes.o test-kprobes-asm.o +obj-$(CONFIG_RISCV_KPROBES_KUNIT) += kprobes_riscv_kunit.o + +kprobes_riscv_kunit-objs := test-kprobes.o test-kprobes-asm.o diff --git a/arch/riscv/kernel/tests/kprobes/test-kprobes.c b/arch/riscv/kernel/tests/kprobes/test-kprobes.c index 0716c88bcec7..664535ca0a98 100644 --- a/arch/riscv/kernel/tests/kprobes/test-kprobes.c +++ b/arch/riscv/kernel/tests/kprobes/test-kprobes.c @@ -54,3 +54,6 @@ static struct kunit_suite kprobes_test_suite = { }; kunit_test_suites(&kprobes_test_suite); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("KUnit test for riscv kprobes"); From 44aa25c000b41d7afcb030ac1b8a38f06dabef0a Mon Sep 17 00:00:00 2001 From: Ben Dooks Date: Fri, 24 Oct 2025 18:16:40 +0100 Subject: [PATCH 6/8] riscv: asm: use .insn for making custom instructions The assembler has .insn for building custom instructions now, so change the .4byte to .insn. This ensures the output is marked as an instruction and not as data which may confuse both debuggers and anything else that relies on this sort of marking. Add an ASM_INSN_I() wrapper in asm.h to allow the selecting of how this is output so older assemblers are still good. Reviewed-by: Andrew Jones Signed-off-by: Ben Dooks Link: https://lore.kernel.org/r/20251024171640.65232-1-ben.dooks@codethink.co.uk Signed-off-by: Paul Walmsley --- arch/riscv/include/asm/asm.h | 6 ++++++ arch/riscv/include/asm/insn-def.h | 8 ++++---- arch/riscv/include/asm/vendor_extensions/mips.h | 6 +++--- 3 files changed, 13 insertions(+), 7 deletions(-) diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h index ac28066bb564..e9e8ba83e632 100644 --- a/arch/riscv/include/asm/asm.h +++ b/arch/riscv/include/asm/asm.h @@ -12,6 +12,12 @@ #define __ASM_STR(x) #x #endif +#ifdef CONFIG_AS_HAS_INSN +#define ASM_INSN_I(__x) ".insn " __x +#else +#define ASM_INSN_I(__x) ".4byte " __x +#endif + #if __riscv_xlen == 64 #define __REG_SEL(a, b) __ASM_STR(a) #elif __riscv_xlen == 32 diff --git a/arch/riscv/include/asm/insn-def.h b/arch/riscv/include/asm/insn-def.h index c9cfcea52cbb..d29da6ccd3dd 100644 --- a/arch/riscv/include/asm/insn-def.h +++ b/arch/riscv/include/asm/insn-def.h @@ -256,10 +256,10 @@ INSN_S(OPCODE_OP_IMM, FUNC3(6), __RS2(3), \ SIMM12((offset) & 0xfe0), RS1(base)) -#define RISCV_PAUSE ".4byte 0x100000f" -#define ZAWRS_WRS_NTO ".4byte 0x00d00073" -#define ZAWRS_WRS_STO ".4byte 0x01d00073" -#define RISCV_NOP4 ".4byte 0x00000013" +#define RISCV_PAUSE ASM_INSN_I("0x100000f") +#define ZAWRS_WRS_NTO ASM_INSN_I("0x00d00073") +#define ZAWRS_WRS_STO ASM_INSN_I("0x01d00073") +#define RISCV_NOP4 ASM_INSN_I("0x00000013") #define RISCV_INSN_NOP4 _AC(0x00000013, U) diff --git a/arch/riscv/include/asm/vendor_extensions/mips.h b/arch/riscv/include/asm/vendor_extensions/mips.h index ea8ca747d691..ffeb12dc17a3 100644 --- a/arch/riscv/include/asm/vendor_extensions/mips.h +++ b/arch/riscv/include/asm/vendor_extensions/mips.h @@ -30,8 +30,8 @@ extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_mips; * allowing any subsequent instructions to fetch. */ -#define MIPS_PAUSE ".4byte 0x00501013\n\t" -#define MIPS_EHB ".4byte 0x00301013\n\t" -#define MIPS_IHB ".4byte 0x00101013\n\t" +#define MIPS_PAUSE ASM_INSN_I("0x00501013\n\t") +#define MIPS_EHB ASM_INSN_I("0x00301013\n\t") +#define MIPS_IHB ASM_INSN_I("0x00101013\n\t") #endif // _ASM_RISCV_VENDOR_EXTENSIONS_MIPS_H From 5228ed2c624449d1a53d1c84ba01c021d2df95c0 Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Sat, 11 Oct 2025 02:47:47 +0200 Subject: [PATCH 7/8] riscv: KGDB: Replace deprecated strcpy in kgdb_arch_handle_qxfer_pkt strcpy() is deprecated because it can cause a buffer overflow when the sizes of the source and the destination are not known at compile time. Use strscpy() instead. Link: https://github.com/KSPP/linux/issues/88 Signed-off-by: Thorsten Blum Link: https://lore.kernel.org/r/20251011004750.461954-1-thorsten.blum@linux.dev Signed-off-by: Paul Walmsley --- arch/riscv/kernel/kgdb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/kgdb.c b/arch/riscv/kernel/kgdb.c index 9f3db3503dab..15fec5d1e6de 100644 --- a/arch/riscv/kernel/kgdb.c +++ b/arch/riscv/kernel/kgdb.c @@ -265,10 +265,10 @@ void kgdb_arch_handle_qxfer_pkt(char *remcom_in_buffer, { if (!strncmp(remcom_in_buffer, gdb_xfer_read_target, sizeof(gdb_xfer_read_target))) - strcpy(remcom_out_buffer, riscv_gdb_stub_target_desc); + strscpy(remcom_out_buffer, riscv_gdb_stub_target_desc, BUFMAX); else if (!strncmp(remcom_in_buffer, gdb_xfer_read_cpuxml, sizeof(gdb_xfer_read_cpuxml))) - strcpy(remcom_out_buffer, riscv_gdb_stub_cpuxml); + strscpy(remcom_out_buffer, riscv_gdb_stub_cpuxml, BUFMAX); } static inline void kgdb_arch_update_addr(struct pt_regs *regs, From 2e448567839c65768486d56612c88cb327d26050 Mon Sep 17 00:00:00 2001 From: Thorsten Blum Date: Tue, 21 Oct 2025 15:51:54 +0200 Subject: [PATCH 8/8] cpuidle: riscv-sbi: Replace deprecated strcpy in sbi_cpuidle_init_cpu strcpy() is deprecated; use strscpy() instead. Link: https://github.com/KSPP/linux/issues/88 Signed-off-by: Thorsten Blum Link: https://lore.kernel.org/r/20251021135155.1409-2-thorsten.blum@linux.dev Signed-off-by: Paul Walmsley --- drivers/cpuidle/cpuidle-riscv-sbi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c index a360bc4d20b7..19be6475d356 100644 --- a/drivers/cpuidle/cpuidle-riscv-sbi.c +++ b/drivers/cpuidle/cpuidle-riscv-sbi.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -303,8 +304,8 @@ static int sbi_cpuidle_init_cpu(struct device *dev, int cpu) drv->states[0].exit_latency = 1; drv->states[0].target_residency = 1; drv->states[0].power_usage = UINT_MAX; - strcpy(drv->states[0].name, "WFI"); - strcpy(drv->states[0].desc, "RISC-V WFI"); + strscpy(drv->states[0].name, "WFI"); + strscpy(drv->states[0].desc, "RISC-V WFI"); /* * If no DT idle states are detected (ret == 0) let the driver