linux-stable.git/tools/bpf, branch linux-5.17.y Linux kernel stable tree bpftool: Fix print error when show bpf map 2022-04-08T11:58:22+00:00 Yafang Shao laoar.shao@gmail.com 2022-03-20T06:08:14+00:00 da18b6e851a51377a4476d032dcccbe055dc2554 [ Upstream commit 1824d8ea75f275a5e69e5f6bc0ffe122ea9b938c ] If there is no btf_id or frozen, it will not show the pids, but the pids don't depend on any one of them. Below is the result after this change: $ ./bpftool map show 2: lpm_trie flags 0x1 key 8B value 8B max_entries 1 memlock 4096B pids systemd(1) 3: lpm_trie flags 0x1 key 20B value 8B max_entries 1 memlock 4096B pids systemd(1) While before this change, the 'pids systemd(1)' can't be displayed. Fixes: 9330986c0300 ("bpf: Add bloom filter map implementation") Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220320060815.7716-1-laoar.shao@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1824d8ea75f275a5e69e5f6bc0ffe122ea9b938c ]

If there is no btf_id or frozen, it will not show the pids, but the pids don't
depend on any one of them.

Below is the result after this change:

  $ ./bpftool map show
  2: lpm_trie  flags 0x1
	key 8B  value 8B  max_entries 1  memlock 4096B
	pids systemd(1)
  3: lpm_trie  flags 0x1
	key 20B  value 8B  max_entries 1  memlock 4096B
	pids systemd(1)

While before this change, the 'pids systemd(1)' can't be displayed.

Fixes: 9330986c0300 ("bpf: Add bloom filter map implementation")
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220320060815.7716-1-laoar.shao@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpftool: Fix pretty print dump for maps without BTF loaded 2022-04-08T11:58:07+00:00 Jiri Olsa jolsa@kernel.org 2022-02-16T09:21:02+00:00 0da0a33b87d1a0715bd5e18c3b77e8dafe8319a7 [ Upstream commit f76d8507d23834f7e56b0fe95c82605e7d7e0efe ] The commit e5043894b21f ("bpftool: Use libbpf_get_error() to check error") fails to dump map without BTF loaded in pretty mode (-p option). Fixing this by making sure get_map_kv_btf won't fail in case there's no BTF available for the map. Fixes: e5043894b21f ("bpftool: Use libbpf_get_error() to check error") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220216092102.125448-1-jolsa@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f76d8507d23834f7e56b0fe95c82605e7d7e0efe ]

The commit e5043894b21f ("bpftool: Use libbpf_get_error() to check error")
fails to dump map without BTF loaded in pretty mode (-p option).

Fixing this by making sure get_map_kv_btf won't fail in case there's
no BTF available for the map.

Fixes: e5043894b21f ("bpftool: Use libbpf_get_error() to check error")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220216092102.125448-1-jolsa@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpftool: Fix the error when lookup in no-btf maps 2022-04-08T11:58:06+00:00 Yinjun Zhang yinjun.zhang@corigine.com 2022-02-07T16:00:25+00:00 e8b42ba320f5fde6eee1c3fb99939ed48e27d899 [ Upstream commit edc21dc909c6c133a2727f063eadd7907af51f94 ] When reworking btf__get_from_id() in commit a19f93cfafdf the error handling when calling bpf_btf_get_fd_by_id() changed. Before the rework if bpf_btf_get_fd_by_id() failed the error would not be propagated to callers of btf__get_from_id(), after the rework it is. This lead to a change in behavior in print_key_value() that now prints an error when trying to lookup keys in maps with no btf available. Fix this by following the way used in dumping maps to allow to look up keys in no-btf maps, by which it decides whether and where to get the btf info according to the btf value type. Fixes: a19f93cfafdf ("libbpf: Add internal helper to load BTF data by FD") Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com> Signed-off-by: Simon Horman <simon.horman@corigine.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/1644249625-22479-1-git-send-email-yinjun.zhang@corigine.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit edc21dc909c6c133a2727f063eadd7907af51f94 ]

When reworking btf__get_from_id() in commit a19f93cfafdf the error
handling when calling bpf_btf_get_fd_by_id() changed. Before the rework
if bpf_btf_get_fd_by_id() failed the error would not be propagated to
callers of btf__get_from_id(), after the rework it is. This lead to a
change in behavior in print_key_value() that now prints an error when
trying to lookup keys in maps with no btf available.

Fix this by following the way used in dumping maps to allow to look up
keys in no-btf maps, by which it decides whether and where to get the
btf info according to the btf value type.

Fixes: a19f93cfafdf ("libbpf: Add internal helper to load BTF data by FD")
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/1644249625-22479-1-git-send-email-yinjun.zhang@corigine.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpftool: Only set obj->skeleton on complete success 2022-04-08T11:57:55+00:00 Wei Fu fuweid89@gmail.com 2022-01-08T08:40:08+00:00 2c14ace87557834a3890a6d614910748fdc858b8 [ Upstream commit 0991f6a38f576aa9a5e34713e23c998a3310d4d0 ] After `bpftool gen skeleton`, the ${bpf_app}.skel.h will provide that ${bpf_app_name}__open helper to load bpf. If there is some error like ENOMEM, the ${bpf_app_name}__open will rollback(free) the allocated object, including `bpf_object_skeleton`. Since the ${bpf_app_name}__create_skeleton set the obj->skeleton first and not rollback it when error, it will cause double-free in ${bpf_app_name}__destory at ${bpf_app_name}__open. Therefore, we should set the obj->skeleton before return 0; Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton") Signed-off-by: Wei Fu <fuweid89@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220108084008.1053111-1-fuweid89@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0991f6a38f576aa9a5e34713e23c998a3310d4d0 ]

After `bpftool gen skeleton`, the ${bpf_app}.skel.h will provide that
${bpf_app_name}__open helper to load bpf. If there is some error
like ENOMEM, the ${bpf_app_name}__open will rollback(free) the allocated
object, including `bpf_object_skeleton`.

Since the ${bpf_app_name}__create_skeleton set the obj->skeleton first
and not rollback it when error, it will cause double-free in
${bpf_app_name}__destory at ${bpf_app_name}__open. Therefore, we should
set the obj->skeleton before return 0;

Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
Signed-off-by: Wei Fu <fuweid89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220108084008.1053111-1-fuweid89@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpftool: Fix error check when calling hashmap__new() 2022-04-08T11:57:55+00:00 Mauricio Vásquez mauricio@kinvolk.io 2022-01-07T15:26:20+00:00 debc1bf7e93d9e682d811c1a5631969baa463808 [ Upstream commit 622a5b582cc27d3deedc38fcef68da2972e8e58d ] hashmap__new() encodes errors with ERR_PTR(), hence it's not valid to check the returned pointer against NULL and IS_ERR() has to be used instead. libbpf_get_error() can't be used in this case as hashmap__new() is not part of the public libbpf API and it'll continue using ERR_PTR() after libbpf 1.0. Fixes: 8f184732b60b ("bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects") Fixes: 2828d0d75b73 ("bpftool: Switch to libbpf's hashmap for programs/maps in BTF listing") Fixes: d6699f8e0f83 ("bpftool: Switch to libbpf's hashmap for PIDs/names references") Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Quentin Monnet <quentin@isovalent.com> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20220107152620.192327-2-mauricio@kinvolk.io Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 622a5b582cc27d3deedc38fcef68da2972e8e58d ]

hashmap__new() encodes errors with ERR_PTR(), hence it's not valid to
check the returned pointer against NULL and IS_ERR() has to be used
instead.

libbpf_get_error() can't be used in this case as hashmap__new() is not
part of the public libbpf API and it'll continue using ERR_PTR() after
libbpf 1.0.

Fixes: 8f184732b60b ("bpftool: Switch to libbpf's hashmap for pinned paths of BPF objects")
Fixes: 2828d0d75b73 ("bpftool: Switch to libbpf's hashmap for programs/maps in BTF listing")
Fixes: d6699f8e0f83 ("bpftool: Switch to libbpf's hashmap for PIDs/names references")
Signed-off-by: Mauricio Vásquez <mauricio@kinvolk.io>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Acked-by: Song Liu <songliubraving@fb.com>
Link: https://lore.kernel.org/bpf/20220107152620.192327-2-mauricio@kinvolk.io
Signed-off-by: Sasha Levin <sashal@kernel.org>
Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2022-02-03T21:42:38+00:00 Jakub Kicinski kuba@kernel.org 2022-02-03T21:42:38+00:00 77b1b8b43ec3c060ecf7e926a92b0f8772171046 Daniel Borkmann says: ==================== pull-request: bpf 2022-02-03 We've added 6 non-merge commits during the last 10 day(s) which contain a total of 7 files changed, 11 insertions(+), 236 deletions(-). The main changes are: 1) Fix BPF ringbuf to allocate its area with VM_MAP instead of VM_ALLOC flag which otherwise trips over KASAN, from Hou Tao. 2) Fix unresolved symbol warning in resolve_btfids due to LSM callback rename, from Alexei Starovoitov. 3) Fix a possible race in inc_misses_counter() when IRQ would trigger during counter update, from He Fengqing. 4) Fix tooling infra for cross-building with clang upon probing whether gcc provides the standard libraries, from Jean-Philippe Brucker. 5) Fix silent mode build for resolve_btfids, from Nathan Chancellor. 6) Drop unneeded and outdated lirc.h header copy from tooling infra as BPF does not require it anymore, from Sean Young. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: tools/resolve_btfids: Do not print any commands when building silently bpf: Use VM_MAP instead of VM_ALLOC for ringbuf tools: Ignore errors from `which' when searching a GCC toolchain tools headers UAPI: remove stale lirc.h bpf: Fix possible race in inc_misses_counter bpf: Fix renaming task_getsecid_subj->current_getsecid_subj. ==================== Link: https://lore.kernel.org/r/20220203155815.25689-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org> 
Daniel Borkmann says:

====================
pull-request: bpf 2022-02-03

We've added 6 non-merge commits during the last 10 day(s) which contain
a total of 7 files changed, 11 insertions(+), 236 deletions(-).

The main changes are:

1) Fix BPF ringbuf to allocate its area with VM_MAP instead of VM_ALLOC
   flag which otherwise trips over KASAN, from Hou Tao.

2) Fix unresolved symbol warning in resolve_btfids due to LSM callback
   rename, from Alexei Starovoitov.

3) Fix a possible race in inc_misses_counter() when IRQ would trigger
   during counter update, from He Fengqing.

4) Fix tooling infra for cross-building with clang upon probing whether
   gcc provides the standard libraries, from Jean-Philippe Brucker.

5) Fix silent mode build for resolve_btfids, from Nathan Chancellor.

6) Drop unneeded and outdated lirc.h header copy from tooling infra as
   BPF does not require it anymore, from Sean Young.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  tools/resolve_btfids: Do not print any commands when building silently
  bpf: Use VM_MAP instead of VM_ALLOC for ringbuf
  tools: Ignore errors from `which' when searching a GCC toolchain
  tools headers UAPI: remove stale lirc.h
  bpf: Fix possible race in inc_misses_counter
  bpf: Fix renaming task_getsecid_subj->current_getsecid_subj.
====================

Link: https://lore.kernel.org/r/20220203155815.25689-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tools/resolve_btfids: Do not print any commands when building silently 2022-02-03T15:28:49+00:00 Nathan Chancellor nathan@kernel.org 2022-02-01T21:25:04+00:00 7f3bdbc3f13146eb9d07de81ea71f551587a384b When building with 'make -s', there is some output from resolve_btfids: $ make -sj"$(nproc)" oldconfig prepare MKDIR .../tools/bpf/resolve_btfids/libbpf/ MKDIR .../tools/bpf/resolve_btfids//libsubcmd LINK resolve_btfids Silent mode means that no information should be emitted about what is currently being done. Use the $(silent) variable from Makefile.include to avoid defining the msg macro so that there is no information printed. Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object") Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220201212503.731732-1-nathan@kernel.org 
When building with 'make -s', there is some output from resolve_btfids:

$ make -sj"$(nproc)" oldconfig prepare
  MKDIR     .../tools/bpf/resolve_btfids/libbpf/
  MKDIR     .../tools/bpf/resolve_btfids//libsubcmd
  LINK     resolve_btfids

Silent mode means that no information should be emitted about what is
currently being done. Use the $(silent) variable from Makefile.include
to avoid defining the msg macro so that there is no information printed.

Fixes: fbbb68de80a4 ("bpf: Add resolve_btfids tool to resolve BTF IDs in ELF object")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220201212503.731732-1-nathan@kernel.org
Merge tag 'powerpc-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 2022-01-23T15:52:42+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-01-23T15:52:42+00:00 dd81e1c7d5fb126e5fbc5c9e334d7b3ec29a16a0 Pull powerpc fixes from Michael Ellerman: - A series of bpf fixes, including an oops fix and some codegen fixes. - Fix a regression in syscall_get_arch() for compat processes. - Fix boot failure on some 32-bit systems with KASAN enabled. - A couple of other build/minor fixes. Thanks to Athira Rajeev, Christophe Leroy, Dmitry V. Levin, Jiri Olsa, Johan Almbladh, Maxime Bizon, Naveen N. Rao, and Nicholas Piggin. * tag 'powerpc-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/64s: Mask SRR0 before checking against the masked NIP powerpc/perf: Only define power_pmu_wants_prompt_pmi() for CONFIG_PPC64 powerpc/32s: Fix kasan_init_region() for KASAN powerpc/time: Fix build failure due to do_hard_irq_enable() on PPC32 powerpc/audit: Fix syscall_get_arch() powerpc64/bpf: Limit 'ldbrx' to processors compliant with ISA v2.06 tools/bpf: Rename 'struct event' to avoid naming conflict powerpc/bpf: Update ldimm64 instructions during extra pass powerpc32/bpf: Fix codegen for bpf-to-bpf calls bpf: Guard against accessing NULL pt_regs in bpf_get_task_stack() 
Pull powerpc fixes from Michael Ellerman:

 - A series of bpf fixes, including an oops fix and some codegen fixes.

 - Fix a regression in syscall_get_arch() for compat processes.

 - Fix boot failure on some 32-bit systems with KASAN enabled.

 - A couple of other build/minor fixes.

Thanks to Athira Rajeev, Christophe Leroy, Dmitry V. Levin, Jiri Olsa,
Johan Almbladh, Maxime Bizon, Naveen N. Rao, and Nicholas Piggin.

* tag 'powerpc-5.17-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: Mask SRR0 before checking against the masked NIP
  powerpc/perf: Only define power_pmu_wants_prompt_pmi() for CONFIG_PPC64
  powerpc/32s: Fix kasan_init_region() for KASAN
  powerpc/time: Fix build failure due to do_hard_irq_enable() on PPC32
  powerpc/audit: Fix syscall_get_arch()
  powerpc64/bpf: Limit 'ldbrx' to processors compliant with ISA v2.06
  tools/bpf: Rename 'struct event' to avoid naming conflict
  powerpc/bpf: Update ldimm64 instructions during extra pass
  powerpc32/bpf: Fix codegen for bpf-to-bpf calls
  bpf: Guard against accessing NULL pt_regs in bpf_get_task_stack()
Merge branch 'akpm' (patches from Andrew) 2022-01-20T08:41:01+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-01-20T08:41:01+00:00 f4484d138b31e8fa1ba410363b5b9664f68974af Merge more updates from Andrew Morton: "55 patches. Subsystems affected by this patch series: percpu, procfs, sysctl, misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2, hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (55 commits) lib: remove redundant assignment to variable ret ubsan: remove CONFIG_UBSAN_OBJECT_SIZE kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB btrfs: use generic Kconfig option for 256kB page size limit arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB configs: introduce debug.config for CI-like setup delayacct: track delays from memory compact Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact delayacct: cleanup flags in struct task_delay_info and functions use it delayacct: fix incomplete disable operation when switch enable to disable delayacct: support swapin delay accounting for swapping without blkio panic: remove oops_id panic: use error_report_end tracepoint on warnings fs/adfs: remove unneeded variable make code cleaner FAT: use io_schedule_timeout() instead of congestion_wait() hfsplus: use struct_group_attr() for memcpy() region nilfs2: remove redundant pointer sbufs fs/binfmt_elf: use PT_LOAD p_align values for static PIE const_structs.checkpatch: add frequently used ops structs ... 
Merge more updates from Andrew Morton:
 "55 patches.

  Subsystems affected by this patch series: percpu, procfs, sysctl,
  misc, core-kernel, get_maintainer, lib, checkpatch, binfmt, nilfs2,
  hfs, fat, adfs, panic, delayacct, kconfig, kcov, and ubsan"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (55 commits)
  lib: remove redundant assignment to variable ret
  ubsan: remove CONFIG_UBSAN_OBJECT_SIZE
  kcov: fix generic Kconfig dependencies if ARCH_WANTS_NO_INSTR
  lib/Kconfig.debug: make TEST_KMOD depend on PAGE_SIZE_LESS_THAN_256KB
  btrfs: use generic Kconfig option for 256kB page size limit
  arch/Kconfig: split PAGE_SIZE_LESS_THAN_256KB from PAGE_SIZE_LESS_THAN_64KB
  configs: introduce debug.config for CI-like setup
  delayacct: track delays from memory compact
  Documentation/accounting/delay-accounting.rst: add thrashing page cache and direct compact
  delayacct: cleanup flags in struct task_delay_info and functions use it
  delayacct: fix incomplete disable operation when switch enable to disable
  delayacct: support swapin delay accounting for swapping without blkio
  panic: remove oops_id
  panic: use error_report_end tracepoint on warnings
  fs/adfs: remove unneeded variable make code cleaner
  FAT: use io_schedule_timeout() instead of congestion_wait()
  hfsplus: use struct_group_attr() for memcpy() region
  nilfs2: remove redundant pointer sbufs
  fs/binfmt_elf: use PT_LOAD p_align values for static PIE
  const_structs.checkpatch: add frequently used ops structs
  ...
tools/bpf/bpftool/skeleton: replace bpf_probe_read_kernel with bpf_probe_read_kernel_str to get task comm 2022-01-20T06:52:53+00:00 Yafang Shao laoar.shao@gmail.com 2022-01-20T02:08:36+00:00 4cfb943537ed3716daf668ca5a33d3ce667f82a3 bpf_probe_read_kernel_str() will add a nul terminator to the dst, then we don't care about if the dst size is big enough. Link: https://lkml.kernel.org/r/20211120112738.45980-7-laoar.shao@gmail.com Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Kees Cook <keescook@chromium.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
bpf_probe_read_kernel_str() will add a nul terminator to the dst, then
we don't care about if the dst size is big enough.

Link: https://lkml.kernel.org/r/20211120112738.45980-7-laoar.shao@gmail.com
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Michal Miroslaw <mirq-linux@rere.qmqm.pl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>