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[PATCH] kprobes: fix bug when probed on task and isr functions

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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 <anil.s.keshavamurthy@intel.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Keshavamurthy Anil S
2005-09-06 15:19:35 -07:00
committed by Linus Torvalds
parent bce0649417
commit deac66ae45
7 changed files with 55 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
arch/ia64/kernel/kprobes.c
View File

@ -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;
}