diff options
| author | Yonghong Song <yhs@fb.com> | 2017-10-23 23:53:08 -0700 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:51:32 +0300 |
| commit | a85b6c28bb287439916716f124450ceb79a1624f (patch) | |
| tree | faa8839e1d97bcd06a42bc681f86df74734d02fb /kernel/trace/trace_syscalls.c | |
| parent | 3f79f14b62202045de323c754352cee2ac3b1d08 (diff) | |
BACKPORT: bpf: permit multiple bpf attachments for a single perf event
This patch enables multiple bpf attachments for a
kprobe/uprobe/tracepoint single trace event.
Each trace_event keeps a list of attached perf events.
When an event happens, all attached bpf programs will
be executed based on the order of attachment.
A global bpf_event_mutex lock is introduced to protect
prog_array attaching and detaching. An alternative will
be introduce a mutex lock in every trace_event_call
structure, but it takes a lot of extra memory.
So a global bpf_event_mutex lock is a good compromise.
The bpf prog detachment involves allocation of memory.
If the allocation fails, a dummy do-nothing program
will replace to-be-detached program in-place.
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit e87c6bc3852b981e71c757be20771546ce9f76f3)
Signed-off-by: Connor O'Brien <connoro@google.com>
Bug: 121213201
Bug: 138317270
Test: build & boot cuttlefish; attach 2 progs to 1 tracepoint
Change-Id: I390d8c0146888ddb1aed5a6f6e5dae7ef394ebc9
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
Diffstat (limited to 'kernel/trace/trace_syscalls.c')
| -rw-r--r-- | kernel/trace/trace_syscalls.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index d7cfb6a673e3..e8540540ecab 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -551,6 +551,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) struct syscall_metadata *sys_data; struct syscall_trace_enter *rec; struct hlist_head *head; + bool valid_prog_array; int syscall_nr; int rctx; int size; @@ -566,7 +567,8 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) return; head = this_cpu_ptr(sys_data->enter_event->perf_events); - if (hlist_empty(head)) + valid_prog_array = bpf_prog_array_valid(sys_data->enter_event); + if (!valid_prog_array && hlist_empty(head)) return; /* get the size after alignment with the u32 buffer size field */ @@ -626,6 +628,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) struct syscall_metadata *sys_data; struct syscall_trace_exit *rec; struct hlist_head *head; + bool valid_prog_array; int syscall_nr; int rctx; int size; @@ -641,7 +644,8 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) return; head = this_cpu_ptr(sys_data->exit_event->perf_events); - if (hlist_empty(head)) + valid_prog_array = bpf_prog_array_valid(sys_data->exit_event); + if (!valid_prog_array && hlist_empty(head)) return; /* We can probably do that at build time */ |