wireguard-linux/arch/s390/kernel/stacktrace.c, branch update-toolchain

s390/stackstrace: Detect vdso stack frames

2024-05-14T11:37:07Z

Clear the backchain of the extra stack frame added by the vdso user wrapper code. This allows the user stack walker to detect and skip the non-standard stack frame. Without this an incorrect instruction pointer would be added to stack traces, and stack frame walking would be continued with a more or less random back chain. Fixes: aa44433ac4ee ("s390: add USER_STACKTRACE support") Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/stacktrace: Improve detection of invalid instruction pointers

2024-05-14T11:37:06Z

Add basic checks to identify invalid instruction pointers when walking stack frames: Instruction pointers must - have even addresses - be larger than mmap_min_addr - lower than the asce_limit of the process Alternatively it would also be possible to walk page tables similar to fast GUP and verify that the mapping of the corresponding page is executable, however that seems to be overkill. Fixes: aa44433ac4ee ("s390: add USER_STACKTRACE support") Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/stacktrace: Skip first user stack frame

2024-05-14T11:37:06Z

When walking user stack frames the first stack frame (where the stack pointer points to) should be skipped: the return address of the current function is saved in the previous stack frame, not the current stack frame, which is allocated for to be called functions. Fixes: aa44433ac4ee ("s390: add USER_STACKTRACE support") Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/stacktrace: Merge perf_callchain_user() and arch_stack_walk_user()

2024-05-14T11:37:06Z

The two functions perf_callchain_user() and arch_stack_walk_user() are nearly identical. Reduce code duplication and add a common helper which can be called by both functions. Fixes: aa44433ac4ee ("s390: add USER_STACKTRACE support") Reviewed-by: Jens Remus Signed-off-by: Heiko Carstens Signed-off-by: Alexander Gordeev

s390/ftrace: Use unwinder instead of __builtin_return_address()

2024-04-29T15:33:30Z

Using __builtin_return_address(n) might return undefined values when used with values of n outside of the stack. This was noticed when __builtin_return_address() was called in ftrace on top level functions like the interrupt handlers. As this behaviour cannot be fixed, use the s390 stack unwinder and remove the ftrace compilation flags for unwind_bc.c and stacktrace.c to prevent the unwinding function polluting function traces. Another advantage is that this also works with clang. Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Alexander Gordeev

s390: add USER_STACKTRACE support

2023-11-05T21:34:57Z

Use the perf_callchain_user() code as blueprint to also add support for USER_STACKTRACE. To describe how to use this cite the commit message of the LoongArch implementation which came with commit 4d7bf939df08 ("LoongArch: Add USER_STACKTRACE support"), but replace -fno-omit-frame-pointer option with the s390 specific -mbackchain option: ====================================================================== To get the best stacktrace output, you can compile your userspace programs with frame pointers (at least glibc + the app you are tracing). 1, export "CC = gcc -mbackchain"; 2, compile your programs with "CC"; 3, use uprobe to get stacktrace output. ... echo 'p:malloc /usr/lib64/libc.so.6:0x0a4704 size=%r2:u64' > uprobe_events echo 'p:free /usr/lib64/libc.so.6:0x0a4d50 ptr=%r2:u64' >> uprobe_events echo 'comm == "demo"' > ./events/uprobes/malloc/filter echo 'comm == "demo"' > ./events/uprobes/free/filter echo 1 > ./options/userstacktrace echo 1 > ./options/sym-userobj ... ====================================================================== Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

s390/kprobes: replace kretprobe with rethook

2023-01-22T17:42:35Z

That's an adaptation of commit f3a112c0c40d ("x86,rethook,kprobes: Replace kretprobe with rethook on x86") to s390. Replaces the kretprobe code with rethook on s390. With this patch, kretprobe on s390 uses the rethook instead of kretprobe specific trampoline code. Tested-by: Ilya Leoshkevich Signed-off-by: Vasily Gorbik Signed-off-by: Heiko Carstens

s390: remove invalid email address of Heiko Carstens

2022-02-06T22:31:29Z

Remove my old invalid email address which can be found in a couple of files. Instead of updating it, just remove my contact data completely from source files. We have git and other tools which allow to figure out who is responsible for what with recent contact data. Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik

kprobes: treewide: Make it harder to refer kretprobe_trampoline directly

2021-10-01T01:24:06Z

Since now there is kretprobe_trampoline_addr() for referring the address of kretprobe trampoline code, we don't need to access kretprobe_trampoline directly. Make it harder to refer by renaming it to __kretprobe_trampoline(). Link: https://lkml.kernel.org/r/163163045446.489837.14510577516938803097.stgit@devnote2 Suggested-by: Ingo Molnar Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

stacktrace: Move documentation for arch_stack_walk_reliable() to header

2021-03-10T14:52:31Z

Currently arch_stack_walk_reliable() is documented with an identical comment in both x86 and S/390 implementations which is a bit redundant. Move this to the header and convert to kerneldoc while we're at it. Signed-off-by: Mark Brown Signed-off-by: Borislav Petkov Reviewed-by: Miroslav Benes Acked-by: Vasily Gorbik Acked-by: Randy Dunlap Link: https://lkml.kernel.org/r/20210309194125.652-1-broonie@kernel.org