-stable review patch. If anyone has any objections, please let us know. ------------------ From: Jeff Dike This patch uses MAX_REG_NR consistently to refer to the register file size. FRAME_SIZE isn't sufficient because on x86_64, it is smaller than the ptrace register file size. MAX_REG_NR was introduced as a consistent way to get the number of registers, but wasn't used everywhere it should be. When this causes a problem, it makes PTRACE_SETREGS fail on x86_64 because of a corrupted segment register value in the known-good register file. The patch also adds a register dump at that point in case there are any future problems here. Signed-off-by: Jeff Dike Signed-off-by: Greg Kroah-Hartman --- arch/um/include/sysdep-x86_64/ptrace.h | 4 ---- arch/um/os-Linux/skas/mem.c | 10 +++++++--- arch/um/os-Linux/skas/process.c | 6 +++--- arch/um/os-Linux/sys-i386/registers.c | 5 +++-- arch/um/os-Linux/sys-x86_64/registers.c | 4 ++-- 5 files changed, 15 insertions(+), 14 deletions(-) --- a/arch/um/include/sysdep-x86_64/ptrace.h +++ b/arch/um/include/sysdep-x86_64/ptrace.h @@ -104,10 +104,6 @@ union uml_pt_regs { #endif #ifdef UML_CONFIG_MODE_SKAS struct skas_regs { - /* x86_64 ptrace uses sizeof(user_regs_struct) as its register - * file size, while i386 uses FRAME_SIZE. Therefore, we need - * to use UM_FRAME_SIZE here instead of HOST_FRAME_SIZE. - */ unsigned long regs[MAX_REG_NR]; unsigned long fp[HOST_FP_SIZE]; struct faultinfo faultinfo; --- a/arch/um/os-Linux/skas/mem.c +++ b/arch/um/os-Linux/skas/mem.c @@ -48,7 +48,7 @@ int multi_op_count = 0; static inline long do_syscall_stub(struct mm_id * mm_idp, void **addr) { unsigned long regs[MAX_REG_NR]; - int n; + int n, i; long ret, offset; unsigned long * data; unsigned long * syscall; @@ -66,9 +66,13 @@ static inline long do_syscall_stub(struc (unsigned long) &__syscall_stub_start); n = ptrace_setregs(pid, regs); - if(n < 0) + if(n < 0){ + printk("Registers - \n"); + for(i = 0; i < MAX_REG_NR; i++) + printk("\t%d\t0x%lx\n", i, regs[i]); panic("do_syscall_stub : PTRACE_SETREGS failed, errno = %d\n", - n); + -n); + } wait_stub_done(pid, 0, "do_syscall_stub"); --- a/arch/um/os-Linux/skas/process.c +++ b/arch/um/os-Linux/skas/process.c @@ -67,7 +67,7 @@ void wait_stub_done(int pid, int sig, ch if((n < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){ - unsigned long regs[HOST_FRAME_SIZE]; + unsigned long regs[MAX_REG_NR]; if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0) printk("Failed to get registers from stub, " @@ -76,7 +76,7 @@ void wait_stub_done(int pid, int sig, ch int i; printk("Stub registers -\n"); - for(i = 0; i < HOST_FRAME_SIZE; i++) + for(i = 0; i < ARRAY_SIZE(regs); i++) printk("\t%d - %lx\n", i, regs[i]); } panic("%s : failed to wait for SIGUSR1/SIGTRAP, " @@ -328,7 +328,7 @@ void userspace(union uml_pt_regs *regs) int copy_context_skas0(unsigned long new_stack, int pid) { int err; - unsigned long regs[HOST_FRAME_SIZE]; + unsigned long regs[MAX_REG_NR]; unsigned long fp_regs[HOST_FP_SIZE]; unsigned long current_stack = current_stub_stack(); struct stub_data *data = (struct stub_data *) current_stack; --- a/arch/um/os-Linux/sys-i386/registers.c +++ b/arch/um/os-Linux/sys-i386/registers.c @@ -15,7 +15,7 @@ /* These are set once at boot time and not changed thereafter */ -static unsigned long exec_regs[HOST_FRAME_SIZE]; +static unsigned long exec_regs[MAX_REG_NR]; static unsigned long exec_fp_regs[HOST_FP_SIZE]; static unsigned long exec_fpx_regs[HOST_XFP_SIZE]; static int have_fpx_regs = 1; @@ -101,6 +101,7 @@ void init_registers(int pid) { int err; + memset(exec_regs, 0, sizeof(exec_regs)); err = ptrace(PTRACE_GETREGS, pid, 0, exec_regs); if(err) panic("check_ptrace : PTRACE_GETREGS failed, errno = %d", @@ -124,7 +125,7 @@ void init_registers(int pid) void get_safe_registers(unsigned long *regs, unsigned long *fp_regs) { - memcpy(regs, exec_regs, HOST_FRAME_SIZE * sizeof(unsigned long)); + memcpy(regs, exec_regs, sizeof(exec_regs)); if(fp_regs != NULL) memcpy(fp_regs, exec_fp_regs, HOST_FP_SIZE * sizeof(unsigned long)); --- a/arch/um/os-Linux/sys-x86_64/registers.c +++ b/arch/um/os-Linux/sys-x86_64/registers.c @@ -14,7 +14,7 @@ /* These are set once at boot time and not changed thereafter */ -static unsigned long exec_regs[HOST_FRAME_SIZE]; +static unsigned long exec_regs[MAX_REG_NR]; static unsigned long exec_fp_regs[HOST_FP_SIZE]; void init_thread_registers(union uml_pt_regs *to) @@ -72,7 +72,7 @@ void init_registers(int pid) void get_safe_registers(unsigned long *regs, unsigned long *fp_regs) { - memcpy(regs, exec_regs, HOST_FRAME_SIZE * sizeof(unsigned long)); + memcpy(regs, exec_regs, sizeof(exec_regs)); if(fp_regs != NULL) memcpy(fp_regs, exec_fp_regs, HOST_FP_SIZE * sizeof(unsigned long)); -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/