Date: Tue, 8 Dec 2020 17:57:18 +0000 (UTC) From: John Baldwin <jhb@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r368454 - in head/sys: cddl/dev/dtrace/riscv cddl/dev/fbt riscv/include riscv/riscv Message-ID: <202012081757.0B8HvIi4078718@repo.freebsd.org>
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Author: jhb Date: Tue Dec 8 17:57:18 2020 New Revision: 368454 URL: https://svnweb.freebsd.org/changeset/base/368454 Log: Stack unwinding robustness fixes for RISC-V. - Push the kstack_contains check down into unwind_frame() so that it is honored by DDB and DTrace. - Check that the trapframe for an exception frame is contained in the traced thread's kernel stack for DDB traces. Reviewed by: markj Obtained from: CheriBSD Sponsored by: DARPA Differential Revision: https://reviews.freebsd.org/D27357 Modified: head/sys/cddl/dev/dtrace/riscv/dtrace_isa.c head/sys/cddl/dev/fbt/fbt.c head/sys/riscv/include/stack.h head/sys/riscv/riscv/db_trace.c head/sys/riscv/riscv/stack_machdep.c head/sys/riscv/riscv/unwind.c Modified: head/sys/cddl/dev/dtrace/riscv/dtrace_isa.c ============================================================================== --- head/sys/cddl/dev/dtrace/riscv/dtrace_isa.c Tue Dec 8 17:44:34 2020 (r368453) +++ head/sys/cddl/dev/dtrace/riscv/dtrace_isa.c Tue Dec 8 17:57:18 2020 (r368454) @@ -90,7 +90,7 @@ dtrace_getpcstack(pc_t *pcstack, int pcstack_limit, in state.pc = (uintptr_t)dtrace_getpcstack; while (depth < pcstack_limit) { - if (unwind_frame(&state)) + if (!unwind_frame(curthread, &state)) break; if (!INKERNEL(state.pc) || !INKERNEL(state.fp)) @@ -259,10 +259,10 @@ dtrace_getstackdepth(int aframes) int scp_offset; register_t sp; int depth; - int done; + bool done; depth = 1; - done = 0; + done = false; __asm __volatile("mv %0, sp" : "=&r" (sp)); @@ -271,7 +271,7 @@ dtrace_getstackdepth(int aframes) state.pc = (uintptr_t)dtrace_getstackdepth; do { - done = unwind_frame(&state); + done = !unwind_frame(curthread, &state); if (!INKERNEL(state.pc) || !INKERNEL(state.fp)) break; depth++; Modified: head/sys/cddl/dev/fbt/fbt.c ============================================================================== --- head/sys/cddl/dev/fbt/fbt.c Tue Dec 8 17:44:34 2020 (r368453) +++ head/sys/cddl/dev/fbt/fbt.c Tue Dec 8 17:57:18 2020 (r368454) @@ -137,6 +137,15 @@ fbt_excluded(const char *name) return (1); /* + * Stack unwinders may be called from probe context on some + * platforms. + */ +#if defined(__riscv) + if (strcmp(name, "unwind_frame") == 0) + return (1); +#endif + + /* * When DTrace is built into the kernel we need to exclude * the FBT functions from instrumentation. */ Modified: head/sys/riscv/include/stack.h ============================================================================== --- head/sys/riscv/include/stack.h Tue Dec 8 17:44:34 2020 (r368453) +++ head/sys/riscv/include/stack.h Tue Dec 8 17:57:18 2020 (r368454) @@ -46,6 +46,6 @@ struct unwind_state { uintptr_t pc; }; -int unwind_frame(struct unwind_state *); +bool unwind_frame(struct thread *, struct unwind_state *); #endif /* !_MACHINE_STACK_H_ */ Modified: head/sys/riscv/riscv/db_trace.c ============================================================================== --- head/sys/riscv/riscv/db_trace.c Tue Dec 8 17:44:34 2020 (r368453) +++ head/sys/riscv/riscv/db_trace.c Tue Dec 8 17:57:18 2020 (r368454) @@ -73,7 +73,7 @@ db_md_set_watchpoint(db_expr_t addr, db_expr_t size) } static void -db_stack_trace_cmd(struct unwind_state *frame) +db_stack_trace_cmd(struct thread *td, struct unwind_state *frame) { const char *name; db_expr_t offset; @@ -100,6 +100,11 @@ db_stack_trace_cmd(struct unwind_state *frame) struct trapframe *tf; tf = (struct trapframe *)(uintptr_t)frame->sp; + if (!kstack_contains(td, (vm_offset_t)tf, + sizeof(*tf))) { + db_printf("--- invalid trapframe %p\n", tf); + break; + } if ((tf->tf_scause & SCAUSE_INTR) != 0) db_printf("--- interrupt %ld\n", @@ -119,7 +124,7 @@ db_stack_trace_cmd(struct unwind_state *frame) if (strcmp(name, "fork_trampoline") == 0) break; - if (unwind_frame(frame) < 0) + if (!unwind_frame(td, frame)) break; } } @@ -135,7 +140,7 @@ db_trace_thread(struct thread *thr, int count) frame.sp = ctx->pcb_sp; frame.fp = ctx->pcb_s[0]; frame.pc = ctx->pcb_ra; - db_stack_trace_cmd(&frame); + db_stack_trace_cmd(thr, &frame); return (0); } @@ -150,5 +155,5 @@ db_trace_self(void) frame.sp = sp; frame.fp = (uintptr_t)__builtin_frame_address(0); frame.pc = (uintptr_t)db_trace_self; - db_stack_trace_cmd(&frame); + db_stack_trace_cmd(curthread, &frame); } Modified: head/sys/riscv/riscv/stack_machdep.c ============================================================================== --- head/sys/riscv/riscv/stack_machdep.c Tue Dec 8 17:44:34 2020 (r368453) +++ head/sys/riscv/riscv/stack_machdep.c Tue Dec 8 17:57:18 2020 (r368454) @@ -53,10 +53,8 @@ stack_capture(struct thread *td, struct stack *st, str stack_zero(st); while (1) { - if (!kstack_contains(td, (vm_offset_t)frame->fp - - (sizeof(uintptr_t) * 2), sizeof(uintptr_t) * 2)) + if (!unwind_frame(td, frame)) break; - unwind_frame(frame); if (!INKERNEL((vm_offset_t)frame->pc)) break; if (stack_put(st, frame->pc) == -1) Modified: head/sys/riscv/riscv/unwind.c ============================================================================== --- head/sys/riscv/riscv/unwind.c Tue Dec 8 17:44:34 2020 (r368453) +++ head/sys/riscv/riscv/unwind.c Tue Dec 8 17:57:18 2020 (r368454) @@ -35,23 +35,24 @@ #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include <sys/param.h> +#include <sys/proc.h> #include <machine/stack.h> #include <machine/vmparam.h> -int -unwind_frame(struct unwind_state *frame) +bool +unwind_frame(struct thread *td, struct unwind_state *frame) { uintptr_t fp; fp = frame->fp; - if (!INKERNEL(fp)) - return (-1); + if (!kstack_contains(td, fp - sizeof(fp) * 2, sizeof(fp) * 2)) + return (false); frame->sp = fp; frame->fp = ((uintptr_t *)fp)[-2]; frame->pc = ((uintptr_t *)fp)[-1] - 4; - return (0); + return (true); }
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