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Protect dtrace_getpcstack() from a NULL stack pointer in a trap frame

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Found when trying to use lockstat on a POWER9, the stack pointer (r1) could
be NULL, and result in a NULL pointer dereference, crashing the kernel.
This commit is contained in:
Justin Hibbits 2018-05-30 03:48:27 +00:00
parent 8b20f97570
commit 5e91185bb1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=334370
1 changed files with 5 additions and 1 deletions
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6
sys/cddl/dev/dtrace/powerpc/dtrace_isa.c
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@ -98,6 +98,7 @@ static __inline uintptr_t
dtrace_next_sp(uintptr_t sp)
{
vm_offset_t callpc;
uintptr_t *r1;
struct trapframe *frame;
#ifdef __powerpc64__
@ -114,7 +115,10 @@ dtrace_next_sp(uintptr_t sp)
callpc + OFFSET == (vm_offset_t) &asttrapexit)) {
/* Access the trap frame */
frame = (struct trapframe *)(sp + FRAME_OFFSET);
return (*(uintptr_t *)(frame->fixreg[1]));
r1 = (uintptr_t *)frame->fixreg[1];
if (r1 == NULL)
return (0);
return (*r1);
}
return (*(uintptr_t*)sp);