linux/kernel/bpf
Jiri Olsa e2bb9e01d5 bpf: Remove trace_printk_lock
Both bpf_trace_printk and bpf_trace_vprintk helpers use static buffer guarded
with trace_printk_lock spin lock.

The spin lock contention causes issues with bpf programs attached to
contention_begin tracepoint [1][2].

Andrii suggested we could get rid of the contention by using trylock, but we
could actually get rid of the spinlock completely by using percpu buffers the
same way as for bin_args in bpf_bprintf_prepare function.

Adding new return 'buf' argument to struct bpf_bprintf_data and making
bpf_bprintf_prepare to return also the buffer for printk helpers.

  [1] https://lore.kernel.org/bpf/CACkBjsakT_yWxnSWr4r-0TpPvbKm9-OBmVUhJb7hV3hY8fdCkw@mail.gmail.com/
  [2] https://lore.kernel.org/bpf/CACkBjsaCsTovQHFfkqJKto6S4Z8d02ud1D7MPESrHa1cVNNTrw@mail.gmail.com/

Reported-by: Hao Sun <sunhao.th@gmail.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20221215214430.1336195-4-jolsa@kernel.org
2022-12-19 22:08:37 +01:00
..
preload bpf: iterators: Build and use lightweight bootstrap version of bpftool 2022-07-15 12:01:30 -07:00
Kconfig rcu: Make the TASKS_RCU Kconfig option be selected 2022-04-20 16:52:58 -07:00
Makefile bpf: Implement cgroup storage available to non-cgroup-attached bpf progs 2022-10-25 23:19:19 -07:00
arraymap.c bpf: Do btf_record_free outside map_free callback 2022-11-17 19:11:31 -08:00
bloom_filter.c treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
bpf_cgrp_storage.c bpf: Fix a compilation failure with clang lto build 2022-11-30 17:13:25 -08:00
bpf_inode_storage.c bpf: Fix a compilation failure with clang lto build 2022-11-30 17:13:25 -08:00
bpf_iter.c bpf: Initialize the bpf_run_ctx in bpf_iter_run_prog() 2022-08-18 17:06:13 -07:00
bpf_local_storage.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-11-29 13:04:52 -08:00
bpf_lru_list.c bpf_lru_list: Read double-checked variable once without lock 2021-02-10 15:54:26 -08:00
bpf_lru_list.h printk: stop including cache.h from printk.h 2022-05-13 07:20:07 -07:00
bpf_lsm.c bpf: Do not mark certain LSM hook arguments as trusted 2022-12-04 12:59:58 -08:00
bpf_struct_ops.c bpf: Remove is_valid_bpf_tramp_flags() 2022-07-11 21:04:58 +02:00
bpf_struct_ops_types.h bpf: Add dummy BPF STRUCT_OPS for test purpose 2021-11-01 14:10:00 -07:00
bpf_task_storage.c bpf: Fix a compilation failure with clang lto build 2022-11-30 17:13:25 -08:00
btf.c for-alexei-2022120701 2022-12-07 13:49:21 -08:00
cgroup.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2022-10-03 17:44:18 -07:00
cgroup_iter.c bpf: Pin the start cgroup in cgroup_iter_seq_init() 2022-11-21 17:40:42 +01:00
core.c Networking changes for 6.2. 2022-12-13 15:47:48 -08:00
cpumap.c bpf: Expand map key argument of bpf_redirect_map to u64 2022-11-15 09:00:27 -08:00
devmap.c bpf: Expand map key argument of bpf_redirect_map to u64 2022-11-15 09:00:27 -08:00
disasm.c bpf: Relicense disassembler as GPL-2.0-only OR BSD-2-Clause 2021-09-02 14:49:23 +02:00
disasm.h bpf: Relicense disassembler as GPL-2.0-only OR BSD-2-Clause 2021-09-02 14:49:23 +02:00
dispatcher.c bpf: Add explicit cast to 'void *' for __BPF_DISPATCHER_UPDATE() 2022-11-07 16:07:35 -08:00
hashtab.c bpf: Do btf_record_free outside map_free callback 2022-11-17 19:11:31 -08:00
helpers.c bpf: Remove trace_printk_lock 2022-12-19 22:08:37 +01:00
inode.c bpf: Convert bpf_preload.ko to use light skeleton. 2022-02-10 23:31:51 +01:00
link_iter.c bpf: Add bpf_link iterator 2022-05-10 11:20:45 -07:00
local_storage.c bpf: Consolidate spin_lock, timer management into btf_record 2022-11-03 22:19:40 -07:00
lpm_trie.c bpf: Use bpf_map_area_alloc consistently on bpf map creation 2022-08-10 11:50:43 -07:00
map_in_map.c bpf: Add comments for map BTF matching requirement for bpf_list_head 2022-11-17 19:22:14 -08:00
map_in_map.h bpf: Add map_meta_equal map ops 2020-08-28 15:41:30 +02:00
map_iter.c bpf: Introduce MEM_RDONLY flag 2021-12-18 13:27:41 -08:00
memalloc.c bpf: Skip rcu_barrier() if rcu_trace_implies_rcu_gp() is true 2022-12-08 17:50:17 -08:00
mmap_unlock_work.h bpf: Introduce helper bpf_find_vma 2021-11-07 11:54:51 -08:00
net_namespace.c net: Add includes masked by netdevice.h including uapi/bpf.h 2021-12-29 20:03:05 -08:00
offload.c bpf: Use bpf_map_area_alloc consistently on bpf map creation 2022-08-10 11:50:43 -07:00
percpu_freelist.c bpf: Initialize same number of free nodes for each pcpu_freelist 2022-11-11 12:05:14 -08:00
percpu_freelist.h bpf: Use raw_spin_trylock() for pcpu_freelist_push/pop in NMI 2020-10-06 00:04:11 +02:00
prog_iter.c
queue_stack_maps.c bpf: Remove unneeded memset in queue_stack_map creation 2022-08-10 11:48:22 -07:00
reuseport_array.c net: Fix suspicious RCU usage in bpf_sk_reuseport_detach() 2022-08-17 16:42:59 -07:00
ringbuf.c bpf: Rename MEM_ALLOC to MEM_RINGBUF 2022-11-14 21:52:45 -08:00
stackmap.c perf/bpf: Always use perf callchains if exist 2022-09-13 15:03:22 +02:00
syscall.c bpf: Add comments for map BTF matching requirement for bpf_list_head 2022-11-17 19:22:14 -08:00
sysfs_btf.c bpf: Load and verify kernel module BTFs 2020-11-10 15:25:53 -08:00
task_iter.c - Yu Zhao's Multi-Gen LRU patches are here. They've been under test in 2022-10-10 17:53:04 -07:00
tnum.c bpf, tnums: Provably sound, faster, and more precise algorithm for tnum_mul 2021-06-01 13:34:15 +02:00
trampoline.c bpf: Remove prog->active check for bpf_lsm and bpf_iter 2022-10-25 23:11:46 -07:00
verifier.c bpf: Add struct for bin_args arg in bpf_bprintf_prepare 2022-12-19 22:07:52 +01:00