From deac66ae454cacf942c051b86d9232af546fb187 Mon Sep 17 00:00:00 2001 From: Keshavamurthy Anil S Date: Tue, 6 Sep 2005 15:19:35 -0700 Subject: [PATCH] kprobes: fix bug when probed on task and isr functions This patch fixes a race condition where in system used to hang or sometime crash within minutes when kprobes are inserted on ISR routine and a task routine. The fix has been stress tested on i386, ia64, pp64 and on x86_64. To reproduce the problem insert kprobes on schedule() and do_IRQ() functions and you should see hang or system crash. Signed-off-by: Anil S Keshavamurthy Signed-off-by: Ananth N Mavinakayanahalli Acked-by: Prasanna S Panchamukhi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/kernel/kprobes.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) (limited to 'arch/ia64/kernel') diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c index 4b1bd539ec47..471086b808a4 100644 --- a/arch/ia64/kernel/kprobes.c +++ b/arch/ia64/kernel/kprobes.c @@ -95,6 +95,17 @@ static void __kprobes update_kprobe_inst_flag(uint template, uint slot, p->ainsn.inst_flag = 0; p->ainsn.target_br_reg = 0; + /* Check for Break instruction + * Bits 37:40 Major opcode to be zero + * Bits 27:32 X6 to be zero + * Bits 32:35 X3 to be zero + */ + if ((!major_opcode) && (!((kprobe_inst >> 27) & 0x1FF)) ) { + /* is a break instruction */ + p->ainsn.inst_flag |= INST_FLAG_BREAK_INST; + return; + } + if (bundle_encoding[template][slot] == B) { switch (major_opcode) { case INDIRECT_CALL_OPCODE: @@ -542,8 +553,11 @@ static void __kprobes prepare_ss(struct kprobe *p, struct pt_regs *regs) unsigned long bundle_addr = (unsigned long) &p->opcode.bundle; unsigned long slot = (unsigned long)p->addr & 0xf; - /* Update instruction pointer (IIP) and slot number (IPSR.ri) */ - regs->cr_iip = bundle_addr & ~0xFULL; + /* single step inline if break instruction */ + if (p->ainsn.inst_flag == INST_FLAG_BREAK_INST) + regs->cr_iip = (unsigned long)p->addr & ~0xFULL; + else + regs->cr_iip = bundle_addr & ~0xFULL; if (slot > 2) slot = 0; @@ -599,7 +613,9 @@ static int __kprobes pre_kprobes_handler(struct die_args *args) if (kprobe_running()) { p = get_kprobe(addr); if (p) { - if (kprobe_status == KPROBE_HIT_SS) { + if ( (kprobe_status == KPROBE_HIT_SS) && + (p->ainsn.inst_flag == INST_FLAG_BREAK_INST)) { + ia64_psr(regs)->ss = 0; unlock_kprobes(); goto no_kprobe; } -- cgit v1.2.1