As reported by lockdep, some patching was done without acquiring text_mutex, so there could be a race when mapping the page to patch since we use the same fixmap entry.
Reported-by: Han Gao <rabenda...@gmail.com> Reported-by: Vivian Wang <wangruik...@iscas.ac.cn> Reported-by: Yao Zi <zi...@disroot.org> Closes: https://lore.kernel.org/linux-riscv/agodmpq7tgind...@pie.lan/ Tested-by: Yao Zi <zi...@disroot.org> Tested-by: Han Gao <rabenda...@gmail.com> Reviewed-by: Masami Hiramatsu (Google) <mhira...@kernel.org> Signed-off-by: Alexandre Ghiti <alexgh...@rivosinc.com> --- Changes in v2: - Add __acquires/__releases annotations (Masami) - Add TB/RB (Masami, Han) - Link to v1: https://lore.kernel.org/r/20250708-alex-fixes-v1-1-5b008d3f4...@rivosinc.com --- arch/riscv/kernel/ftrace.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/arch/riscv/kernel/ftrace.c b/arch/riscv/kernel/ftrace.c index 4c6c24380cfd9d6c51f0e4340cd674160b83a610..8d18d6727f0fc8fa17d8f651b9e3a00c779cec85 100644 --- a/arch/riscv/kernel/ftrace.c +++ b/arch/riscv/kernel/ftrace.c @@ -14,6 +14,18 @@ #include <asm/text-patching.h> #ifdef CONFIG_DYNAMIC_FTRACE +void ftrace_arch_code_modify_prepare(void) + __acquires(&text_mutex) +{ + mutex_lock(&text_mutex); +} + +void ftrace_arch_code_modify_post_process(void) + __releases(&text_mutex) +{ + mutex_unlock(&text_mutex); +} + unsigned long ftrace_call_adjust(unsigned long addr) { if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)) @@ -29,10 +41,8 @@ unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) void arch_ftrace_update_code(int command) { - mutex_lock(&text_mutex); command |= FTRACE_MAY_SLEEP; ftrace_modify_all_code(command); - mutex_unlock(&text_mutex); flush_icache_all(); } @@ -149,6 +159,8 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) unsigned int nops[2], offset; int ret; + guard(mutex)(&text_mutex); + ret = ftrace_rec_set_nop_ops(rec); if (ret) return ret; @@ -157,9 +169,7 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) nops[0] = to_auipc_t0(offset); nops[1] = RISCV_INSN_NOP4; - mutex_lock(&text_mutex); ret = patch_insn_write((void *)pc, nops, 2 * MCOUNT_INSN_SIZE); - mutex_unlock(&text_mutex); return ret; } --- base-commit: d7b8f8e20813f0179d8ef519541a3527e7661d3a change-id: 20250708-alex-fixes-1e719b9899f3 Best regards, -- Alexandre Ghiti <alexgh...@rivosinc.com>
