diff options
author | Linus Torvalds | 2024-07-18 12:19:20 -0700 |
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committer | Linus Torvalds | 2024-07-18 12:19:20 -0700 |
commit | 91bd008d4e2b4962ecb9a10e40c2fb666b0aeb92 (patch) | |
tree | c63456ce31eef7c07c1313715a0e24242bf4c92e /kernel/events | |
parent | cb273eb7c8390c70a484db6c79a797e377db09b5 (diff) | |
parent | c26b1b89b8a9fd8665e79cd798bd970e233772b6 (diff) |
Merge tag 'probes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes updates from Masami Hiramatsu:
"Uprobes:
- x86/shstk: Make return uprobe work with shadow stack
- Add uretprobe syscall which speeds up the uretprobe 10-30% faster.
This syscall is automatically used from user-space trampolines
which are generated by the uretprobe. If this syscall is used by
normal user program, it will cause SIGILL. Note that this is
currently only implemented on x86_64.
(This also has two fixes for adjusting the syscall number to avoid
conflict with new *attrat syscalls.)
- uprobes/perf: fix user stack traces in the presence of pending
uretprobe. This corrects the uretprobe's trampoline address in the
stacktrace with correct return address
- selftests/x86: Add a return uprobe with shadow stack test
- selftests/bpf: Add uretprobe syscall related tests.
- test case for register integrity check
- test case with register changing case
- test case for uretprobe syscall without uprobes (expected to fail)
- test case for uretprobe with shadow stack
- selftests/bpf: add test validating uprobe/uretprobe stack traces
- MAINTAINERS: Add uprobes entry. This does not specify the tree but
to clarify who maintains and reviews the uprobes
Kprobes:
- tracing/kprobes: Test case cleanups.
Replace redundant WARN_ON_ONCE() + pr_warn() with WARN_ONCE() and
remove unnecessary code from selftest
- tracing/kprobes: Add symbol counting check when module loads.
This checks the uniqueness of the probed symbol on modules. The
same check has already done for kernel symbols
(This also has a fix for build error with CONFIG_MODULES=n)
Cleanup:
- Add MODULE_DESCRIPTION() macros for fprobe and kprobe examples"
* tag 'probes-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
MAINTAINERS: Add uprobes entry
selftests/bpf: Change uretprobe syscall number in uprobe_syscall test
uprobe: Change uretprobe syscall scope and number
tracing/kprobes: Fix build error when find_module() is not available
tracing/kprobes: Add symbol counting check when module loads
selftests/bpf: add test validating uprobe/uretprobe stack traces
perf,uprobes: fix user stack traces in the presence of pending uretprobes
tracing/kprobe: Remove cleanup code unrelated to selftest
tracing/kprobe: Integrate test warnings into WARN_ONCE
selftests/bpf: Add uretprobe shadow stack test
selftests/bpf: Add uretprobe syscall call from user space test
selftests/bpf: Add uretprobe syscall test for regs changes
selftests/bpf: Add uretprobe syscall test for regs integrity
selftests/x86: Add return uprobe shadow stack test
uprobe: Add uretprobe syscall to speed up return probe
uprobe: Wire up uretprobe system call
x86/shstk: Make return uprobe work with shadow stack
samples: kprobes: add missing MODULE_DESCRIPTION() macros
fprobe: add missing MODULE_DESCRIPTION() macro
Diffstat (limited to 'kernel/events')
-rw-r--r-- | kernel/events/callchain.c | 43 | ||||
-rw-r--r-- | kernel/events/uprobes.c | 33 |
2 files changed, 68 insertions, 8 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c index ad57944b6c40..8d57255e5b29 100644 --- a/kernel/events/callchain.c +++ b/kernel/events/callchain.c @@ -11,6 +11,7 @@ #include <linux/perf_event.h> #include <linux/slab.h> #include <linux/sched/task_stack.h> +#include <linux/uprobes.h> #include "internal.h" @@ -176,13 +177,51 @@ put_callchain_entry(int rctx) put_recursion_context(this_cpu_ptr(callchain_recursion), rctx); } +static void fixup_uretprobe_trampoline_entries(struct perf_callchain_entry *entry, + int start_entry_idx) +{ +#ifdef CONFIG_UPROBES + struct uprobe_task *utask = current->utask; + struct return_instance *ri; + __u64 *cur_ip, *last_ip, tramp_addr; + + if (likely(!utask || !utask->return_instances)) + return; + + cur_ip = &entry->ip[start_entry_idx]; + last_ip = &entry->ip[entry->nr - 1]; + ri = utask->return_instances; + tramp_addr = uprobe_get_trampoline_vaddr(); + + /* + * If there are pending uretprobes for the current thread, they are + * recorded in a list inside utask->return_instances; each such + * pending uretprobe replaces traced user function's return address on + * the stack, so when stack trace is captured, instead of seeing + * actual function's return address, we'll have one or many uretprobe + * trampoline addresses in the stack trace, which are not helpful and + * misleading to users. + * So here we go over the pending list of uretprobes, and each + * encountered trampoline address is replaced with actual return + * address. + */ + while (ri && cur_ip <= last_ip) { + if (*cur_ip == tramp_addr) { + *cur_ip = ri->orig_ret_vaddr; + ri = ri->next; + } + cur_ip++; + } +#endif +} + struct perf_callchain_entry * get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, u32 max_stack, bool crosstask, bool add_mark) { struct perf_callchain_entry *entry; struct perf_callchain_entry_ctx ctx; - int rctx; + int rctx, start_entry_idx; entry = get_callchain_entry(&rctx); if (!entry) @@ -215,7 +254,9 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, if (add_mark) perf_callchain_store_context(&ctx, PERF_CONTEXT_USER); + start_entry_idx = entry->nr; perf_callchain_user(&ctx, regs); + fixup_uretprobe_trampoline_entries(entry, start_entry_idx); } } diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 2c83ba776fc7..99be2adedbc0 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1474,11 +1474,20 @@ static int xol_add_vma(struct mm_struct *mm, struct xol_area *area) return ret; } +void * __weak arch_uprobe_trampoline(unsigned long *psize) +{ + static uprobe_opcode_t insn = UPROBE_SWBP_INSN; + + *psize = UPROBE_SWBP_INSN_SIZE; + return &insn; +} + static struct xol_area *__create_xol_area(unsigned long vaddr) { struct mm_struct *mm = current->mm; - uprobe_opcode_t insn = UPROBE_SWBP_INSN; + unsigned long insns_size; struct xol_area *area; + void *insns; area = kmalloc(sizeof(*area), GFP_KERNEL); if (unlikely(!area)) @@ -1502,7 +1511,8 @@ static struct xol_area *__create_xol_area(unsigned long vaddr) /* Reserve the 1st slot for get_trampoline_vaddr() */ set_bit(0, area->bitmap); atomic_set(&area->slot_count, 1); - arch_uprobe_copy_ixol(area->pages[0], 0, &insn, UPROBE_SWBP_INSN_SIZE); + insns = arch_uprobe_trampoline(&insns_size); + arch_uprobe_copy_ixol(area->pages[0], 0, insns, insns_size); if (!xol_add_vma(mm, area)) return area; @@ -1827,7 +1837,7 @@ void uprobe_copy_process(struct task_struct *t, unsigned long flags) * * Returns -1 in case the xol_area is not allocated. */ -static unsigned long get_trampoline_vaddr(void) +unsigned long uprobe_get_trampoline_vaddr(void) { struct xol_area *area; unsigned long trampoline_vaddr = -1; @@ -1878,7 +1888,7 @@ static void prepare_uretprobe(struct uprobe *uprobe, struct pt_regs *regs) if (!ri) return; - trampoline_vaddr = get_trampoline_vaddr(); + trampoline_vaddr = uprobe_get_trampoline_vaddr(); orig_ret_vaddr = arch_uretprobe_hijack_return_addr(trampoline_vaddr, regs); if (orig_ret_vaddr == -1) goto fail; @@ -2123,7 +2133,7 @@ static struct return_instance *find_next_ret_chain(struct return_instance *ri) return ri; } -static void handle_trampoline(struct pt_regs *regs) +void uprobe_handle_trampoline(struct pt_regs *regs) { struct uprobe_task *utask; struct return_instance *ri, *next; @@ -2149,6 +2159,15 @@ static void handle_trampoline(struct pt_regs *regs) instruction_pointer_set(regs, ri->orig_ret_vaddr); do { + /* pop current instance from the stack of pending return instances, + * as it's not pending anymore: we just fixed up original + * instruction pointer in regs and are about to call handlers; + * this allows fixup_uretprobe_trampoline_entries() to properly fix up + * captured stack traces from uretprobe handlers, in which pending + * trampoline addresses on the stack are replaced with correct + * original return addresses + */ + utask->return_instances = ri->next; if (valid) handle_uretprobe_chain(ri, regs); ri = free_ret_instance(ri); @@ -2187,8 +2206,8 @@ static void handle_swbp(struct pt_regs *regs) int is_swbp; bp_vaddr = uprobe_get_swbp_addr(regs); - if (bp_vaddr == get_trampoline_vaddr()) - return handle_trampoline(regs); + if (bp_vaddr == uprobe_get_trampoline_vaddr()) + return uprobe_handle_trampoline(regs); uprobe = find_active_uprobe(bp_vaddr, &is_swbp); if (!uprobe) { |