Hi again, after sending this out, I noticed this is only a problem in the stable versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as 03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") which makes always use of get_entry_ip. I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0 series as well as otherwise it can't be compiled with -Werror if CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
- Jonas
On Thu, Nov 03, 2022 at 04:03:03PM +0100, Jonas Rabenstein wrote:
Commit c09eb2e578eb1668bbc ("bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT") introduced the get_entry_ip() function. Depending on CONFIG_X86_KERNEL_IBT it is a static function or only a macro definition. The only user of this symbol so far is in kprobe_multi_link_handler() if CONFIG_FPROBE is enabled. If CONFIG_FROBE is not set, the symbol is not used and - depending on CONFIG_X86_KERNEL_IBT - a warning for get_entry_ip() is emitted. To solve this, the function should be marked as __maybe_unused.
Signed-off-by: Jonas Rabenstein rabenstein@cs.fau.de
kernel/trace/bpf_trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f2d8d070d024..19131aae0bc3 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1032,7 +1032,7 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = { }; #ifdef CONFIG_X86_KERNEL_IBT -static unsigned long get_entry_ip(unsigned long fentry_ip) +static unsigned long __maybe_unused get_entry_ip(unsigned long fentry_ip) { u32 instr; -- 2.37.4
On 11/3/22 4:32 PM, Jonas Rabenstein wrote:
Hi again, after sending this out, I noticed this is only a problem in the stable versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as 03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") which makes always use of get_entry_ip. I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0 series as well as otherwise it can't be compiled with -Werror if CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
Thanks for the info, Jonas. Added Greg wrt stable cherry-pick.
On Thu, Nov 03, 2022 at 04:03:03PM +0100, Jonas Rabenstein wrote:
Commit c09eb2e578eb1668bbc ("bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT") introduced the get_entry_ip() function. Depending on CONFIG_X86_KERNEL_IBT it is a static function or only a macro definition. The only user of this symbol so far is in kprobe_multi_link_handler() if CONFIG_FPROBE is enabled. If CONFIG_FROBE is not set, the symbol is not used and - depending on CONFIG_X86_KERNEL_IBT - a warning for get_entry_ip() is emitted. To solve this, the function should be marked as __maybe_unused.
Signed-off-by: Jonas Rabenstein rabenstein@cs.fau.de
kernel/trace/bpf_trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index f2d8d070d024..19131aae0bc3 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1032,7 +1032,7 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = { }; #ifdef CONFIG_X86_KERNEL_IBT -static unsigned long get_entry_ip(unsigned long fentry_ip) +static unsigned long __maybe_unused get_entry_ip(unsigned long fentry_ip) { u32 instr; -- 2.37.4
On Thu, Nov 03, 2022 at 04:32:47PM +0100, Jonas Rabenstein wrote:
Hi again, after sending this out, I noticed this is only a problem in the stable versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as 03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") which makes always use of get_entry_ip. I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0 series as well as otherwise it can't be compiled with -Werror if CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
Ok, now queued up, thanks.
greg k-h
On Mon, Nov 07, 2022 at 09:56:42AM +0100, Greg KH wrote:
On Thu, Nov 03, 2022 at 04:32:47PM +0100, Jonas Rabenstein wrote:
Hi again, after sending this out, I noticed this is only a problem in the stable versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as 03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") which makes always use of get_entry_ip. I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0 series as well as otherwise it can't be compiled with -Werror if CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
Ok, now queued up, thanks.
Oops, this breaks the build, now dropping.
greg k-h
On Mon, Nov 07, 2022 at 10:29:55AM +0100, Greg KH wrote:
On Mon, Nov 07, 2022 at 09:56:42AM +0100, Greg KH wrote:
On Thu, Nov 03, 2022 at 04:32:47PM +0100, Jonas Rabenstein wrote:
Hi again, after sending this out, I noticed this is only a problem in the stable versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as 03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") which makes always use of get_entry_ip. I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0 series as well as otherwise it can't be compiled with -Werror if CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
Ok, now queued up, thanks.
Oops, this breaks the build, now dropping.
Sorry, 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") uses the macro KPROBE_FLAG_ON_FUNC_ENTRY that was introduced in bf7a87f1075f67c286f7 ("kprobes: Add new KPROBE_FLAG_ON_FUNC_ENTRY kprobe flag"). Applying those on top of v6.0.7 fixes the original compilation problem (CONFIG_X6_KERNEL_IBT but !CONFIG_FPROBE) and should not break anything - jonas
greg k-h
On Mon, Nov 07, 2022 at 10:48:49AM +0100, Jonas Rabenstein wrote:
On Mon, Nov 07, 2022 at 10:29:55AM +0100, Greg KH wrote:
On Mon, Nov 07, 2022 at 09:56:42AM +0100, Greg KH wrote:
On Thu, Nov 03, 2022 at 04:32:47PM +0100, Jonas Rabenstein wrote:
Hi again, after sending this out, I noticed this is only a problem in the stable versions (starting from v6.0.3), as c09eb2e578eb1668bbc has been applied (as 03f148c159a250dd454) but not 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") which makes always use of get_entry_ip. I therefore think, 0e253f7e558a3e250902 needs to be added to the stable v6.0 series as well as otherwise it can't be compiled with -Werror if CONFIG_X6_KERNEL_IBT is set but CONFIG_FPROBE isn't.
Ok, now queued up, thanks.
Oops, this breaks the build, now dropping.
Sorry, 0e253f7e558a3e250902 ("bpf: Return value in kprobe get_func_ip only for entry address") uses the macro KPROBE_FLAG_ON_FUNC_ENTRY that was introduced in bf7a87f1075f67c286f7 ("kprobes: Add new KPROBE_FLAG_ON_FUNC_ENTRY kprobe flag"). Applying those on top of v6.0.7 fixes the original compilation problem (CONFIG_X6_KERNEL_IBT but !CONFIG_FPROBE) and should not break anything
Please submit a set of backports that you have verified works properly so that I know it is correct.
thanks,
greg k-h
linux-stable-mirror@lists.linaro.org
-
Daniel Borkmann -
Greg KH -
Jonas Rabenstein