From 2b97956af60810cd382b86b9ce9aea421b889861 Mon Sep 17 00:00:00 2001 From: Nuoqi Gui Date: Fri, 4 Sep 2026 12:41:55 +0200 Subject: selftests/bpf: Test rhtab kptr cancellation semantics Resizable hash-map updates and deletions must not perform full special-field destruction in their caller context. In particular, a referenced kptr must remain attached to the allocation until the memory allocator destructor can release it safely. Add separate coverage for both affected paths. The update test stores a task kptr, replaces the ordinary value bytes with BPF_EXIST, and verifies that the kptr survived. The delete test removes an element and exchanges its kptr through the still-valid map-value pointer before the allocation is reclaimed. Both cases observe a NULL kptr when rhtab uses bpf_obj_free_fields(). They recover and release the reference after rhtab switches to cancellation semantics. Signed-off-by: Nuoqi Gui [ kkd: Split update and delete coverage and rewrote the commit log ] Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904104203.345917-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- include/trace/syscall.h | 57 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) create mode 100644 include/trace/syscall.h (limited to 'include/trace/syscall.h') diff --git a/include/trace/syscall.h b/include/trace/syscall.h new file mode 100644 index 000000000..0dd7f2b33 --- /dev/null +++ b/include/trace/syscall.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _TRACE_SYSCALL_H +#define _TRACE_SYSCALL_H + +#include +#include +#include +#include + +#include + + +/* + * A syscall entry in the ftrace syscalls array. + * + * @name: name of the syscall + * @syscall_nr: number of the syscall + * @nb_args: number of parameters it takes + * @user_arg_is_str: set if the arg for @user_arg_size is a string + * @user_arg_size: holds @arg that has size of the user space to read + * @user_mask: mask of @args that will read user space + * @types: list of types as strings + * @args: list of args as strings (args[i] matches types[i]) + * @enter_fields: list of fields for syscall_enter trace event + * @enter_event: associated syscall_enter trace event + * @exit_event: associated syscall_exit trace event + */ +struct syscall_metadata { + const char *name; + int syscall_nr; + u8 nb_args:7; + u8 user_arg_is_str:1; + s8 user_arg_size; + short user_mask; + const char **types; + const char **args; + struct list_head enter_fields; + + struct trace_event_call *enter_event; + struct trace_event_call *exit_event; +}; + +#if defined(CONFIG_TRACEPOINTS) && defined(CONFIG_HAVE_SYSCALL_TRACEPOINTS) +static inline void syscall_tracepoint_update(struct task_struct *p) +{ + if (test_syscall_work(SYSCALL_TRACEPOINT)) + set_task_syscall_work(p, SYSCALL_TRACEPOINT); + else + clear_task_syscall_work(p, SYSCALL_TRACEPOINT); +} +#else +static inline void syscall_tracepoint_update(struct task_struct *p) +{ +} +#endif + +#endif /* _TRACE_SYSCALL_H */ -- cgit v1.3.1