| Message ID | 20210725173845.2593626-6-andrii@kernel.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | BPF perf link and user-provided context value | expand |
Hi Andrii,
I love your patch! Yet something to improve:
[auto build test ERROR on bpf-next/master]
url: https://github.com/0day-ci/linux/commits/Andrii-Nakryiko/BPF-perf-link-and-user-provided-context-value/20210726-014304
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: s390-randconfig-r002-20210725 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project c63dbd850182797bc4b76124d08e1c320ab2365d)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# install s390 cross compiling tool for clang build
# apt-get install binutils-s390x-linux-gnu
# https://github.com/0day-ci/linux/commit/7832c315a55580b578d21777a0c9476c62edd503
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Andrii-Nakryiko/BPF-perf-link-and-user-provided-context-value/20210726-014304
git checkout 7832c315a55580b578d21777a0c9476c62edd503
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross O=build_dir ARCH=s390 SHELL=/bin/bash kernel/events/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
In file included from kernel/events/core.c:20:
In file included from include/linux/tick.h:8:
In file included from include/linux/clockchips.h:14:
In file included from include/linux/clocksource.h:22:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:464:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __raw_readb(PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:477:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:36:59: note: expanded from macro '__le16_to_cpu'
#define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
^
include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
#define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
^
In file included from kernel/events/core.c:20:
In file included from include/linux/tick.h:8:
In file included from include/linux/clockchips.h:14:
In file included from include/linux/clocksource.h:22:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:490:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
~~~~~~~~~~ ^
include/uapi/linux/byteorder/big_endian.h:34:59: note: expanded from macro '__le32_to_cpu'
#define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
^
include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
#define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
^
In file included from kernel/events/core.c:20:
In file included from include/linux/tick.h:8:
In file included from include/linux/clockchips.h:14:
In file included from include/linux/clocksource.h:22:
In file included from arch/s390/include/asm/io.h:75:
include/asm-generic/io.h:501:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writeb(value, PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:511:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:521:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
__raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
~~~~~~~~~~ ^
include/asm-generic/io.h:609:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:617:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:625:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
readsl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:634:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesb(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:643:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesw(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
include/asm-generic/io.h:652:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
writesl(PCI_IOBASE + addr, buffer, count);
~~~~~~~~~~ ^
>> kernel/events/core.c:10073:5: error: conflicting types for 'perf_event_set_bpf_prog'
int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
^
include/linux/trace_events.h:807:5: note: previous declaration is here
int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 user_ctx);
^
12 warnings and 1 error generated.
vim +/perf_event_set_bpf_prog +10073 kernel/events/core.c
6fb2915df7f074 kernel/perf_event.c Li Zefan 2009-10-15 10072
aebdacfee76037 kernel/events/core.c Andrii Nakryiko 2021-07-25 @10073 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10074 {
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10075 return -ENOENT;
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10076 }
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10077
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi Andrii,
I love your patch! Yet something to improve:
[auto build test ERROR on bpf-next/master]
url: https://github.com/0day-ci/linux/commits/Andrii-Nakryiko/BPF-perf-link-and-user-provided-context-value/20210726-014304
base: https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: nds32-defconfig (attached as .config)
compiler: nds32le-linux-gcc (GCC) 10.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/7832c315a55580b578d21777a0c9476c62edd503
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Andrii-Nakryiko/BPF-perf-link-and-user-provided-context-value/20210726-014304
git checkout 7832c315a55580b578d21777a0c9476c62edd503
# save the attached .config to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross O=build_dir ARCH=nds32 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All errors (new ones prefixed by >>):
>> kernel/events/core.c:10073:5: error: conflicting types for 'perf_event_set_bpf_prog'
10073 | int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
| ^~~~~~~~~~~~~~~~~~~~~~~
In file included from include/trace/syscall.h:7,
from include/linux/syscalls.h:87,
from kernel/events/core.c:34:
include/linux/trace_events.h:807:5: note: previous declaration of 'perf_event_set_bpf_prog' was here
807 | int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 user_ctx);
| ^~~~~~~~~~~~~~~~~~~~~~~
vim +/perf_event_set_bpf_prog +10073 kernel/events/core.c
6fb2915df7f074 kernel/perf_event.c Li Zefan 2009-10-15 10072
aebdacfee76037 kernel/events/core.c Andrii Nakryiko 2021-07-25 @10073 int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog)
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10074 {
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10075 return -ENOENT;
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10076 }
2541517c32be25 kernel/events/core.c Alexei Starovoitov 2015-03-25 10077
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index afae0afe3f81..7490494273e4 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -160,7 +160,7 @@ static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) goto unlock; } - ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); + ret = bpf_prog_array_copy(old_array, NULL, prog, 0, &new_array); if (ret < 0) goto unlock; @@ -193,7 +193,7 @@ static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) } old_array = lirc_rcu_dereference(raw->progs); - ret = bpf_prog_array_copy(old_array, prog, NULL, &new_array); + ret = bpf_prog_array_copy(old_array, prog, NULL, 0, &new_array); /* * Do not use bpf_prog_array_delete_safe() as we would end up * with a dummy entry in the array, and the we would free the diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 9c44b56b698f..74b35faf0b73 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1114,7 +1114,10 @@ u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, */ struct bpf_prog_array_item { struct bpf_prog *prog; - struct bpf_cgroup_storage *cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]; + union { + struct bpf_cgroup_storage *cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]; + u64 user_ctx; + }; }; struct bpf_prog_array { @@ -1140,6 +1143,7 @@ int bpf_prog_array_copy_info(struct bpf_prog_array *array, int bpf_prog_array_copy(struct bpf_prog_array *old_array, struct bpf_prog *exclude_prog, struct bpf_prog *include_prog, + u64 include_user_ctx, struct bpf_prog_array **new_array); struct bpf_run_ctx {}; @@ -1149,6 +1153,11 @@ struct bpf_cg_run_ctx { const struct bpf_prog_array_item *prog_item; }; +struct bpf_trace_run_ctx { + struct bpf_run_ctx run_ctx; + u64 user_ctx; +}; + #ifdef CONFIG_BPF_SYSCALL static inline struct bpf_run_ctx *bpf_set_run_ctx(struct bpf_run_ctx *new_ctx) { @@ -1247,6 +1256,8 @@ BPF_PROG_RUN_ARRAY(const struct bpf_prog_array __rcu *array_rcu, const struct bpf_prog_array_item *item; const struct bpf_prog *prog; const struct bpf_prog_array *array; + struct bpf_run_ctx *old_run_ctx; + struct bpf_trace_run_ctx run_ctx; u32 ret = 1; migrate_disable(); @@ -1254,11 +1265,14 @@ BPF_PROG_RUN_ARRAY(const struct bpf_prog_array __rcu *array_rcu, array = rcu_dereference(array_rcu); if (unlikely(!array)) goto out; + old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx); item = &array->items[0]; while ((prog = READ_ONCE(item->prog))) { + run_ctx.user_ctx = item->user_ctx; ret &= run_prog(prog, ctx); item++; } + bpf_reset_run_ctx(old_run_ctx); out: rcu_read_unlock(); migrate_enable(); diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 2d510ad750ed..97ab46802800 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -762,6 +762,7 @@ struct perf_event { #ifdef CONFIG_BPF_SYSCALL perf_overflow_handler_t orig_overflow_handler; struct bpf_prog *prog; + u64 user_ctx; #endif #ifdef CONFIG_EVENT_TRACING diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index 66eb15d1bc2c..6bcc6ab1ada7 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -676,7 +676,7 @@ trace_trigger_soft_disabled(struct trace_event_file *file) #ifdef CONFIG_BPF_EVENTS unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx); -int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog); +int perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 user_ctx); void perf_event_detach_bpf_prog(struct perf_event *event); int perf_event_query_prog_array(struct perf_event *event, void __user *info); int bpf_probe_register(struct bpf_raw_event_map *btp, struct bpf_prog *prog); @@ -693,7 +693,7 @@ static inline unsigned int trace_call_bpf(struct trace_event_call *call, void *c } static inline int -perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog) +perf_event_attach_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 user_ctx) { return -EOPNOTSUPP; } @@ -804,7 +804,7 @@ extern void ftrace_profile_free_filter(struct perf_event *event); void perf_trace_buf_update(void *record, u16 type); void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp); -int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog); +int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, u64 user_ctx); void perf_event_free_bpf_prog(struct perf_event *event); void bpf_trace_run1(struct bpf_prog *prog, u64 arg1); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 00b1267ab4f0..bc1fd54a8f58 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1448,6 +1448,13 @@ union bpf_attr { __aligned_u64 iter_info; /* extra bpf_iter_link_info */ __u32 iter_info_len; /* iter_info length */ }; + struct { + /* black box user-provided value passed through + * to BPF program at the execution time and + * accessible through bpf_get_user_ctx() BPF helper + */ + __u64 user_ctx; + } perf_event; }; } link_create; diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 9b1577498373..7e4c8bf3e8d1 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2097,13 +2097,13 @@ int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, int bpf_prog_array_copy(struct bpf_prog_array *old_array, struct bpf_prog *exclude_prog, struct bpf_prog *include_prog, + u64 include_user_ctx, struct bpf_prog_array **new_array) { int new_prog_cnt, carry_prog_cnt = 0; - struct bpf_prog_array_item *existing; + struct bpf_prog_array_item *existing, *new; struct bpf_prog_array *array; bool found_exclude = false; - int new_prog_idx = 0; /* Figure out how many existing progs we need to carry over to * the new array. @@ -2140,20 +2140,27 @@ int bpf_prog_array_copy(struct bpf_prog_array *old_array, array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); if (!array) return -ENOMEM; + new = array->items; /* Fill in the new prog array */ if (carry_prog_cnt) { existing = old_array->items; - for (; existing->prog; existing++) - if (existing->prog != exclude_prog && - existing->prog != &dummy_bpf_prog.prog) { - array->items[new_prog_idx++].prog = - existing->prog; - } + for (; existing->prog; existing++) { + if (existing->prog == exclude_prog || + existing->prog == &dummy_bpf_prog.prog) + continue; + + new->prog = existing->prog; + new->user_ctx = existing->user_ctx; + new++; + } } - if (include_prog) - array->items[new_prog_idx++].prog = include_prog; - array->items[new_prog_idx].prog = NULL; + if (include_prog) { + new->prog = include_prog; + new->user_ctx = include_user_ctx; + new++; + } + new->prog = NULL; *new_array = array; return 0; } diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 3d752a5ecc44..f5992cfa9e5b 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2962,7 +2962,7 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro } event = perf_file->private_data; - err = perf_event_set_bpf_prog(event, prog); + err = perf_event_set_bpf_prog(event, prog, attr->link_create.perf_event.user_ctx); if (err) { bpf_link_cleanup(&link_primer); goto out_put_file; diff --git a/kernel/events/core.c b/kernel/events/core.c index b125943599ce..0b5e4a0ef016 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -5643,7 +5643,7 @@ static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned lon if (IS_ERR(prog)) return PTR_ERR(prog); - err = perf_event_set_bpf_prog(event, prog); + err = perf_event_set_bpf_prog(event, prog, 0); if (err) { bpf_prog_put(prog); return err; @@ -9936,7 +9936,9 @@ static void bpf_overflow_handler(struct perf_event *event, event->orig_overflow_handler(event, data, regs); } -static int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog *prog) +static int perf_event_set_bpf_handler(struct perf_event *event, + struct bpf_prog *prog, + u64 user_ctx) { if (event->overflow_handler_context) /* hw breakpoint or kernel counter */ @@ -9966,6 +9968,7 @@ static int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog } event->prog = prog; + event->user_ctx = user_ctx; event->orig_overflow_handler = READ_ONCE(event->overflow_handler); WRITE_ONCE(event->overflow_handler, bpf_overflow_handler); return 0; @@ -9983,7 +9986,9 @@ static void perf_event_free_bpf_handler(struct perf_event *event) bpf_prog_put(prog); } #else -static int perf_event_set_bpf_handler(struct perf_event *event, struct bpf_prog *prog) +static int perf_event_set_bpf_handler(struct perf_event *event, + struct bpf_prog *prog, + u64 user_ctx) { return -EOPNOTSUPP; } @@ -10011,12 +10016,13 @@ static inline bool perf_event_is_tracing(struct perf_event *event) return false; } -int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog) +int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, + u64 user_ctx) { bool is_kprobe, is_tracepoint, is_syscall_tp; if (!perf_event_is_tracing(event)) - return perf_event_set_bpf_handler(event, prog); + return perf_event_set_bpf_handler(event, prog, user_ctx); is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE; is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT; @@ -10042,7 +10048,7 @@ int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog) return -EACCES; } - return perf_event_attach_bpf_prog(event, prog); + return perf_event_attach_bpf_prog(event, prog, user_ctx); } void perf_event_free_bpf_prog(struct perf_event *event) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index b427eac10780..c9cf6a0d0fb3 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1674,7 +1674,8 @@ static DEFINE_MUTEX(bpf_event_mutex); #define BPF_TRACE_MAX_PROGS 64 int perf_event_attach_bpf_prog(struct perf_event *event, - struct bpf_prog *prog) + struct bpf_prog *prog, + u64 user_ctx) { struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; @@ -1701,12 +1702,13 @@ int perf_event_attach_bpf_prog(struct perf_event *event, goto unlock; } - ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); + ret = bpf_prog_array_copy(old_array, NULL, prog, user_ctx, &new_array); if (ret < 0) goto unlock; /* set the new array to event->tp_event and set event->prog */ event->prog = prog; + event->user_ctx = user_ctx; rcu_assign_pointer(event->tp_event->prog_array, new_array); bpf_prog_array_free(old_array); @@ -1727,7 +1729,7 @@ void perf_event_detach_bpf_prog(struct perf_event *event) goto unlock; old_array = bpf_event_rcu_dereference(event->tp_event->prog_array); - ret = bpf_prog_array_copy(old_array, event->prog, NULL, &new_array); + ret = bpf_prog_array_copy(old_array, event->prog, NULL, 0, &new_array); if (ret == -ENOENT) goto unlock; if (ret < 0) { diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 00b1267ab4f0..bc1fd54a8f58 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1448,6 +1448,13 @@ union bpf_attr { __aligned_u64 iter_info; /* extra bpf_iter_link_info */ __u32 iter_info_len; /* iter_info length */ }; + struct { + /* black box user-provided value passed through + * to BPF program at the execution time and + * accessible through bpf_get_user_ctx() BPF helper + */ + __u64 user_ctx; + } perf_event; }; } link_create;
Add ability for users to specify custom u64 value when creating BPF link for perf_event-backed BPF programs (kprobe/uprobe, perf_event, tracepoints). This is useful for cases when the same BPF program is used for attaching and processing invocation of different tracepoints/kprobes/uprobes in a generic fashion, but such that each invocation is distinguished from each other (e.g., BPF program can look up additional information associated with a specific kernel function without having to rely on function IP lookups). This enables new use cases to be implemented simply and efficiently that previously were possible only through code generation (and thus multiple instances of almost identical BPF program) or compilation at runtime (BCC-style) on target hosts (even more expensive resource-wise). For uprobes it is not even possible in some cases to know function IP before hand (e.g., when attaching to shared library without PID filtering, in which case base load address is not known for a library). This is done by storing u64 user_ctx in struct bpf_prog_array_item, corresponding to each attached and run BPF program. Given cgroup BPF programs already use 2 8-byte pointers for their needs and cgroup BPF programs don't have (yet?) support for user_ctx, reuse that space through union of cgroup_storage and new user_ctx field. Make it available to kprobe/tracepoint BPF programs through bpf_trace_run_ctx. This is set by BPF_PROG_RUN_ARRAY, used by kprobe/uprobe/tracepoint BPF program execution code, which luckily is now also split from BPF_PROG_RUN_ARRAY_CG. This run context will be utilized by a new BPF helper giving access to this user context value from inside a BPF program. Generic perf_event BPF programs will access this value from perf_event itself through passed in BPF program context. Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- drivers/media/rc/bpf-lirc.c | 4 ++-- include/linux/bpf.h | 16 +++++++++++++++- include/linux/perf_event.h | 1 + include/linux/trace_events.h | 6 +++--- include/uapi/linux/bpf.h | 7 +++++++ kernel/bpf/core.c | 29 ++++++++++++++++++----------- kernel/bpf/syscall.c | 2 +- kernel/events/core.c | 18 ++++++++++++------ kernel/trace/bpf_trace.c | 8 +++++--- tools/include/uapi/linux/bpf.h | 7 +++++++ 10 files changed, 71 insertions(+), 27 deletions(-)