Hello, This is the 9th version of the series to fix the stacktrace with kretprobe on x86. The previous version is; https://lore.kernel.org/bpf/162399992186.506599.8457763707951687195.stgit@devnote2/ This version is mostly cleaning up changelogs, comments, and coding styles accoding to Ingo's comment. This series also depends on my kprobe cleanup series (*1) and Josh's objtool update series (*2)(*3) (*1) https://lore.kernel.org/bpf/162598881438.1222130.11530594038964049135.stgit@devnote2/ (*2) https://lore.kernel.org/bpf/20210710192433.x5cgjsq2ksvaqnss@treble/ (*3) https://lore.kernel.org/bpf/20210710192514.ghvksi3ozhez4lvb@treble/ Changes from v8: [1/14] - Update changelog and add stable to Cc. [2/14] - Update changelog. [3/14] - Update changelog. [4/14] - Newly added accoding to Ingo's suggestion. [5/14] - Update changelog and comments. - Consolidate the prototypes in the header file. - Make __kretprobe_find_ret_addr() return 'kprobe_opcode_t *'. [6/14] - Update changelog and comments. - Use STACK_FRAME_NON_STANDARD_FP(). [8/14] - Fix "space at the start of a line" checkpatch warnings. [9/14] - Update changelog. [10/14] - Update comments to explain why this is needed. [11/14] - Update changelog and comments. - Remove unneeded type casting. [12/14] - Update comments. [14/14] - Fix the changelog and add more comments. All over this series, I fixed my typo on Andrii's name (I'm sorry). With this series, unwinder can unwind stack correctly from ftrace as below; # cd /sys/kernel/debug/tracing # echo > trace # echo 1 > options/sym-offset # echo r vfs_read >> kprobe_events # echo r full_proxy_read >> kprobe_events # echo traceoff:1 > events/kprobes/r_vfs_read_0/trigger # echo stacktrace:1 > events/kprobes/r_full_proxy_read_0/trigger # echo 1 > events/kprobes/enable # cat /sys/kernel/debug/kprobes/list ffffffff8133b740 r full_proxy_read+0x0 [FTRACE] ffffffff812560b0 r vfs_read+0x0 [FTRACE] # echo 0 > events/kprobes/enable # cat trace # tracer: nop # # entries-in-buffer/entries-written: 3/3 #P:8 # # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | <...>-134 [007] ...1 16.185877: r_full_proxy_read_0: (vfs_read+0x98/0x180 <- full_proxy_read) <...>-134 [007] ...1 16.185901: <stack trace> => kretprobe_trace_func+0x209/0x300 => kretprobe_dispatcher+0x4a/0x70 => __kretprobe_trampoline_handler+0xd4/0x170 => trampoline_handler+0x43/0x60 => kretprobe_trampoline+0x2a/0x50 => vfs_read+0x98/0x180 => ksys_read+0x5f/0xe0 => do_syscall_64+0x37/0x90 => entry_SYSCALL_64_after_hwframe+0x44/0xae <...>-134 [007] ...1 16.185902: r_vfs_read_0: (ksys_read+0x5f/0xe0 <- vfs_read) This shows the double return probes (vfs_read() and full_proxy_read()) on the stack correctly unwinded. (vfs_read() returns to 'ksys_read+0x5f' and full_proxy_read() returns to 'vfs_read+0x98') This also changes the kretprobe behavisor a bit, now the instraction pointer in the 'pt_regs' passed to kretprobe user handler is correctly set the real return address. So user handlers can get it via instruction_pointer() API, and can use stack_trace_save_regs(). You can also get this series from git://git.kernel.org/pub/scm/linux/kernel/git/mhiramat/linux.git kprobes/kretprobe-stackfix-v9 Thank you, --- Josh Poimboeuf (1): x86/kprobes: Add UNWIND_HINT_FUNC on kretprobe_trampoline() Masami Hiramatsu (13): ia64: kprobes: Fix to pass correct trampoline address to the handler kprobes: treewide: Replace arch_deref_entry_point() with dereference_symbol_descriptor() kprobes: treewide: Remove trampoline_address from kretprobe_trampoline_handler() kprobes: treewide: Make it harder to refer kretprobe_trampoline directly kprobes: Add kretprobe_find_ret_addr() for searching return address ARC: Add instruction_pointer_set() API ia64: Add instruction_pointer_set() API arm: kprobes: Make space for instruction pointer on stack kprobes: Enable stacktrace from pt_regs in kretprobe handler x86/kprobes: Push a fake return address at kretprobe_trampoline x86/unwind: Recover kretprobe trampoline entry tracing: Show kretprobe unknown indicator only for kretprobe_trampoline x86/kprobes: Fixup return address in generic trampoline handler arch/arc/include/asm/kprobes.h | 2 arch/arc/include/asm/ptrace.h | 5 + arch/arc/kernel/kprobes.c | 13 ++- arch/arm/probes/kprobes/core.c | 11 +- arch/arm64/include/asm/kprobes.h | 2 arch/arm64/kernel/probes/kprobes.c | 5 - arch/arm64/kernel/probes/kprobes_trampoline.S | 4 - arch/csky/include/asm/kprobes.h | 2 arch/csky/kernel/probes/kprobes.c | 4 - arch/csky/kernel/probes/kprobes_trampoline.S | 4 - arch/ia64/include/asm/ptrace.h | 5 + arch/ia64/kernel/kprobes.c | 15 +-- arch/mips/kernel/kprobes.c | 15 ++- arch/parisc/kernel/kprobes.c | 6 + arch/powerpc/include/asm/kprobes.h | 2 arch/powerpc/kernel/kprobes.c | 29 ++---- arch/powerpc/kernel/optprobes.c | 2 arch/powerpc/kernel/stacktrace.c | 2 arch/riscv/include/asm/kprobes.h | 2 arch/riscv/kernel/probes/kprobes.c | 4 - arch/riscv/kernel/probes/kprobes_trampoline.S | 4 - arch/s390/include/asm/kprobes.h | 2 arch/s390/kernel/kprobes.c | 12 +-- arch/s390/kernel/stacktrace.c | 2 arch/sh/include/asm/kprobes.h | 2 arch/sh/kernel/kprobes.c | 12 +-- arch/sparc/include/asm/kprobes.h | 2 arch/sparc/kernel/kprobes.c | 12 +-- arch/x86/include/asm/kprobes.h | 1 arch/x86/include/asm/unwind.h | 23 +++++ arch/x86/include/asm/unwind_hints.h | 5 + arch/x86/kernel/kprobes/core.c | 71 ++++++++++++--- arch/x86/kernel/unwind_frame.c | 3 - arch/x86/kernel/unwind_guess.c | 3 - arch/x86/kernel/unwind_orc.c | 21 ++++- include/linux/kprobes.h | 44 ++++++++-- kernel/kprobes.c | 115 ++++++++++++++++++------- kernel/trace/trace_output.c | 17 +--- lib/error-inject.c | 3 - 39 files changed, 317 insertions(+), 171 deletions(-) -- Masami Hiramatsu (Linaro) <mhiramat@xxxxxxxxxx>
