Let do_kunwind() and kunwind_stack_walk() return the state of stack walk properly to the caller, and use them in arch_stack_walk_reliable(). This can be used to enable livepatching for arm64.
Signed-off-by: Song Liu <[email protected]> --- arch/arm64/Kconfig | 2 +- arch/arm64/kernel/stacktrace.c | 35 +++++++++++++++++++++++++++------- 2 files changed, 29 insertions(+), 8 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 213f42d5ca27..f5af6faf9e2b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -271,6 +271,7 @@ config ARM64 select HAVE_SOFTIRQ_ON_OWN_STACK select USER_STACKTRACE_SUPPORT select VDSO_GETRANDOM + select HAVE_RELIABLE_STACKTRACE help ARM 64-bit (AArch64) Linux support. @@ -2495,4 +2496,3 @@ endmenu # "CPU Power Management" source "drivers/acpi/Kconfig" source "arch/arm64/kvm/Kconfig" - diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c index 1d9d51d7627f..280dd6839a18 100644 --- a/arch/arm64/kernel/stacktrace.c +++ b/arch/arm64/kernel/stacktrace.c @@ -277,22 +277,28 @@ kunwind_next(struct kunwind_state *state) typedef bool (*kunwind_consume_fn)(const struct kunwind_state *state, void *cookie); -static __always_inline void +static __always_inline int do_kunwind(struct kunwind_state *state, kunwind_consume_fn consume_state, void *cookie) { + int ret; + if (kunwind_recover_return_address(state)) - return; + return -EINVAL; while (1) { - int ret; - if (!consume_state(state, cookie)) + ret = consume_state(state, cookie); + if (!ret) break; ret = kunwind_next(state); if (ret < 0) break; } + /* Unwind terminated successfully */ + if (ret == -ENOENT) + ret = 0; + return ret; } /* @@ -324,7 +330,7 @@ do_kunwind(struct kunwind_state *state, kunwind_consume_fn consume_state, : stackinfo_get_unknown(); \ }) -static __always_inline void +static __always_inline int kunwind_stack_walk(kunwind_consume_fn consume_state, void *cookie, struct task_struct *task, struct pt_regs *regs) @@ -352,7 +358,7 @@ kunwind_stack_walk(kunwind_consume_fn consume_state, if (regs) { if (task != current) - return; + return -EINVAL; kunwind_init_from_regs(&state, regs); } else if (task == current) { kunwind_init_from_caller(&state); @@ -360,7 +366,7 @@ kunwind_stack_walk(kunwind_consume_fn consume_state, kunwind_init_from_task(&state, task); } - do_kunwind(&state, consume_state, cookie); + return do_kunwind(&state, consume_state, cookie); } struct kunwind_consume_entry_data { @@ -387,6 +393,21 @@ noinline noinstr void arch_stack_walk(stack_trace_consume_fn consume_entry, kunwind_stack_walk(arch_kunwind_consume_entry, &data, task, regs); } +noinline noinstr int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, + void *cookie, struct task_struct *task) +{ + int ret; + + struct kunwind_consume_entry_data data = { + .consume_entry = consume_entry, + .cookie = cookie, + }; + + ret = kunwind_stack_walk(arch_kunwind_consume_entry, &data, task, NULL); + + return ret; +} + struct bpf_unwind_consume_entry_data { bool (*consume_entry)(void *cookie, u64 ip, u64 sp, u64 fp); void *cookie; -- 2.43.5
