From 377fad3acbb7e94ab9942a74e0d9ede8eeb2f039 Mon Sep 17 00:00:00 2001 From: Jeff Dike Date: Sun, 6 May 2007 14:51:25 -0700 Subject: uml: kernel segfaults should dump proper registers If there's a segfault inside the kernel, we want a dump of the registers at the point of the segfault, not the registers at the point of calling panic or the last userspace registers. sig_handler_common_skas now uses a static register set in the case of a SIGSEGV to avoid messing up the process registers if the segfault turns out to be non-fatal. The architecture sigcontext-to-pt_regs copying code was repurposed to copy data out of the SEGV stack frame. Signed-off-by: Jeff Dike Cc: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/os-Linux/skas/trap.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) (limited to 'arch/um/os-Linux') diff --git a/arch/um/os-Linux/skas/trap.c b/arch/um/os-Linux/skas/trap.c index 6a20d08caf91..5110eff51b90 100644 --- a/arch/um/os-Linux/skas/trap.c +++ b/arch/um/os-Linux/skas/trap.c @@ -15,6 +15,8 @@ #include "sysdep/ptrace_user.h" #include "os.h" +static union uml_pt_regs ksig_regs[UM_NR_CPUS]; + void sig_handler_common_skas(int sig, void *sc_ptr) { struct sigcontext *sc = sc_ptr; @@ -27,10 +29,19 @@ void sig_handler_common_skas(int sig, void *sc_ptr) * the process will die. * XXX Figure out why this is better than SA_NODEFER */ - if(sig == SIGSEGV) + if(sig == SIGSEGV) { change_sig(SIGSEGV, 1); + /* For segfaults, we want the data from the + * sigcontext. In this case, we don't want to mangle + * the process registers, so use a static set of + * registers. For other signals, the process + * registers are OK. + */ + r = &ksig_regs[cpu()]; + copy_sc(r, sc_ptr); + } + else r = TASK_REGS(get_current()); - r = TASK_REGS(get_current()); save_user = r->skas.is_user; r->skas.is_user = 0; if ( sig == SIGFPE || sig == SIGSEGV || -- cgit v1.2.3