Message ID | 4fedad69107b7fd81b9324315ce4fbf6287e5084.1560868106.git.naveen.n.rao@linux.vnet.ibm.com (mailing list archive) |
---|---|
State | Superseded |
Headers | show |
Series | powerpc/ftrace: Patch out -mprofile-kernel instructions | expand |
Context | Check | Description |
---|---|---|
snowpatch_ozlabs/apply_patch | success | Successfully applied on branch next (e610a466d16a086e321f0bd421e2fc75cff28605) |
snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 36 lines checked |
On Tue, 18 Jun 2019 20:17:05 +0530 "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> wrote: > Ftrace location could include more than a single instruction in case of > some architectures (powerpc64, for now). In this case, kprobe is > permitted on any of those instructions, and uses ftrace infrastructure > for functioning. > > However, [dis]arm_kprobe_ftrace() uses the kprobe address when setting > up ftrace filter IP. This won't work if the address points to any > instruction apart from the one that has a branch to _mcount(). To > resolve this, have [dis]arm_kprobe_ftrace() use ftrace_function() to > identify the filter IP. This looks good to me. Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Thank you! > > Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> > --- > kernel/kprobes.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 445337c107e0..282ee704e2d8 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -978,10 +978,10 @@ static int prepare_kprobe(struct kprobe *p) > /* Caller must lock kprobe_mutex */ > static int arm_kprobe_ftrace(struct kprobe *p) > { > + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); > int ret = 0; > > - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, > - (unsigned long)p->addr, 0, 0); > + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 0, 0); > if (ret) { > pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", > p->addr, ret); > @@ -1005,13 +1005,14 @@ static int arm_kprobe_ftrace(struct kprobe *p) > * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental > * empty filter_hash which would undesirably trace all functions. > */ > - ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0); > + ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); > return ret; > } > > /* Caller must lock kprobe_mutex */ > static int disarm_kprobe_ftrace(struct kprobe *p) > { > + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); > int ret = 0; > > if (kprobe_ftrace_enabled == 1) { > @@ -1022,8 +1023,7 @@ static int disarm_kprobe_ftrace(struct kprobe *p) > > kprobe_ftrace_enabled--; > > - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, > - (unsigned long)p->addr, 1, 0); > + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); > WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", > p->addr, ret); > return ret; > -- > 2.22.0 >
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 445337c107e0..282ee704e2d8 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -978,10 +978,10 @@ static int prepare_kprobe(struct kprobe *p) /* Caller must lock kprobe_mutex */ static int arm_kprobe_ftrace(struct kprobe *p) { + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); int ret = 0; - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, - (unsigned long)p->addr, 0, 0); + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 0, 0); if (ret) { pr_debug("Failed to arm kprobe-ftrace at %pS (%d)\n", p->addr, ret); @@ -1005,13 +1005,14 @@ static int arm_kprobe_ftrace(struct kprobe *p) * non-empty filter_hash for IPMODIFY ops, we're safe from an accidental * empty filter_hash which would undesirably trace all functions. */ - ftrace_set_filter_ip(&kprobe_ftrace_ops, (unsigned long)p->addr, 1, 0); + ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); return ret; } /* Caller must lock kprobe_mutex */ static int disarm_kprobe_ftrace(struct kprobe *p) { + unsigned long ftrace_ip = ftrace_location((unsigned long)p->addr); int ret = 0; if (kprobe_ftrace_enabled == 1) { @@ -1022,8 +1023,7 @@ static int disarm_kprobe_ftrace(struct kprobe *p) kprobe_ftrace_enabled--; - ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, - (unsigned long)p->addr, 1, 0); + ret = ftrace_set_filter_ip(&kprobe_ftrace_ops, ftrace_ip, 1, 0); WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (%d)\n", p->addr, ret); return ret;
Ftrace location could include more than a single instruction in case of some architectures (powerpc64, for now). In this case, kprobe is permitted on any of those instructions, and uses ftrace infrastructure for functioning. However, [dis]arm_kprobe_ftrace() uses the kprobe address when setting up ftrace filter IP. This won't work if the address points to any instruction apart from the one that has a branch to _mcount(). To resolve this, have [dis]arm_kprobe_ftrace() use ftrace_function() to identify the filter IP. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> --- kernel/kprobes.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)