linux-stable.git/kernel/bpf/helpers.c, branch linux-rolling-lts Linux kernel stable tree bpf: Consistently use bpf_rcu_lock_held() everywhere 2026-07-24T14:17:23+00:00 Andrii Nakryiko andrii@kernel.org 2026-07-18T11:44:40+00:00 8fccaeeb9e9c5685ea1799f1abd0c35709413f82 [ Upstream commit 48a97ffc6c826640907d13b199e29008f4fe2c15 ] We have many places which open-code what's now is bpf_rcu_lock_held() macro, so replace all those places with a clean and short macro invocation. For that, move bpf_rcu_lock_held() macro into include/linux/bpf.h. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20251014201403.4104511-1-andrii@kernel.org Stable-dep-of: 2f884d371faf ("bpf: Allow LPM map access from sleepable BPF programs") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 48a97ffc6c826640907d13b199e29008f4fe2c15 ]

We have many places which open-code what's now is bpf_rcu_lock_held()
macro, so replace all those places with a clean and short macro invocation.
For that, move bpf_rcu_lock_held() macro into include/linux/bpf.h.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20251014201403.4104511-1-andrii@kernel.org
Stable-dep-of: 2f884d371faf ("bpf: Allow LPM map access from sleepable BPF programs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
bpf: Fix NULL pointer dereference in bpf_task_from_vpid() 2026-07-24T14:16:03+00:00 Sechang Lim rhkrqnwk98@gmail.com 2026-06-08T05:00:00+00:00 b7474f4432dd9559ada03b01a8cd3472cd02c61d [ Upstream commit 50dff00615522f3ec03449680ca23beb4cfc549c ] bpf_task_from_vpid() looks up a task in the pid namespace of the current task, via find_task_by_vpid(): find_task_by_vpid(vpid) find_task_by_pid_ns(vpid, task_active_pid_ns(current)) find_pid_ns(nr, ns) -> idr_find(&ns->idr, nr) cgroup_skb programs run in softirq, which may interrupt a task that is itself in do_exit(). Once that task has passed exit_notify() -> release_task() -> __unhash_process(), its thread_pid is cleared, so task_active_pid_ns(current) returns NULL and find_pid_ns() dereferences &NULL->idr: BUG: kernel NULL pointer dereference, address: 0000000000000050 RIP: 0010:idr_find+0x11/0x30 lib/idr.c:176 Call Trace: <IRQ> find_pid_ns kernel/pid.c:370 [inline] find_task_by_pid_ns+0x3b/0xe0 kernel/pid.c:485 bpf_task_from_vpid+0x5b/0x200 kernel/bpf/helpers.c:2916 bpf_prog_run_array_cg+0x17e/0x530 kernel/bpf/cgroup.c:81 __cgroup_bpf_run_filter_skb+0x12b/0x250 kernel/bpf/cgroup.c:1612 sk_filter_trim_cap+0x1dc/0x4c0 net/core/filter.c:148 tcp_v4_rcv+0x18d1/0x2200 net/ipv4/tcp_ipv4.c:2223 </IRQ> <TASK> do_exit+0xa63/0x1270 kernel/exit.c:1010 get_signal+0x141c/0x1530 kernel/signal.c:3037 Bail out when current has no pid namespace. Fixes: 675c3596ff32 ("bpf: Add bpf_task_from_vpid() kfunc") Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com> Acked-by: Leon Hwang <leon.hwang@linux.dev> Link: https://lore.kernel.org/bpf/20260608050001.2545245-1-rhkrqnwk98@gmail.com Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 50dff00615522f3ec03449680ca23beb4cfc549c ]

bpf_task_from_vpid() looks up a task in the pid namespace of the
current task, via find_task_by_vpid():

  find_task_by_vpid(vpid)
    find_task_by_pid_ns(vpid, task_active_pid_ns(current))
      find_pid_ns(nr, ns) -> idr_find(&ns->idr, nr)

cgroup_skb programs run in softirq, which may interrupt a task that is
itself in do_exit(). Once that task has passed
exit_notify() -> release_task() -> __unhash_process(), its thread_pid is
cleared, so task_active_pid_ns(current) returns NULL and find_pid_ns()
dereferences &NULL->idr:

  BUG: kernel NULL pointer dereference, address: 0000000000000050
  RIP: 0010:idr_find+0x11/0x30 lib/idr.c:176
  Call Trace:
   <IRQ>
   find_pid_ns kernel/pid.c:370 [inline]
   find_task_by_pid_ns+0x3b/0xe0 kernel/pid.c:485
   bpf_task_from_vpid+0x5b/0x200 kernel/bpf/helpers.c:2916
   bpf_prog_run_array_cg+0x17e/0x530 kernel/bpf/cgroup.c:81
   __cgroup_bpf_run_filter_skb+0x12b/0x250 kernel/bpf/cgroup.c:1612
   sk_filter_trim_cap+0x1dc/0x4c0 net/core/filter.c:148
   tcp_v4_rcv+0x18d1/0x2200 net/ipv4/tcp_ipv4.c:2223
   </IRQ>
   <TASK>
   do_exit+0xa63/0x1270 kernel/exit.c:1010
   get_signal+0x141c/0x1530 kernel/signal.c:3037

Bail out when current has no pid namespace.

Fixes: 675c3596ff32 ("bpf: Add bpf_task_from_vpid() kfunc")
Signed-off-by: Sechang Lim <rhkrqnwk98@gmail.com>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/bpf/20260608050001.2545245-1-rhkrqnwk98@gmail.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpf: Clear rb node linkage when freeing bpf_rb_root 2026-07-24T14:16:02+00:00 Kaitao Cheng chengkaitao@kylinos.cn 2026-06-05T09:41:43+00:00 2eb39de4962f842d653e96818ae372665cd481fd [ Upstream commit 4a7910ee060d8ce55612f5b3cc267f3a265a3cec ] bpf_rb_root_free() detaches the root by copying the current rb_root_cached and then replacing the live root with RB_ROOT_CACHED. It then walks the copied root and drops each object contained in the tree. This leaves the rb node state intact while dropping the object. If the object is refcounted and survives the drop, its bpf_rb_node_kern still contains an owner pointer to the freed root and stale rb tree linkage. If a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove() can incorrectly pass the owner check and call rb_erase_cached() on a node whose rb pointers belong to the old tree. Mirror the list draining behavior by marking nodes as busy while the root is being detached, then clear the rb node and release the owner before dropping the containing object. This makes surviving nodes unowned and safe to reject from remove or accept for a later add. Fixes: 9c395c1b99bd ("bpf: Add basic bpf_rb_{root,node} support") Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/r/20260605094143.5509-1-kaitao.cheng@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 4a7910ee060d8ce55612f5b3cc267f3a265a3cec ]

bpf_rb_root_free() detaches the root by copying the current rb_root_cached
and then replacing the live root with RB_ROOT_CACHED. It then walks the
copied root and drops each object contained in the tree.

This leaves the rb node state intact while dropping the object. If the
object is refcounted and survives the drop, its bpf_rb_node_kern still
contains an owner pointer to the freed root and stale rb tree linkage. If
a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove()
can incorrectly pass the owner check and call rb_erase_cached() on a node
whose rb pointers belong to the old tree.

Mirror the list draining behavior by marking nodes as busy while the root
is being detached, then clear the rb node and release the owner before
dropping the containing object. This makes surviving nodes unowned and
safe to reject from remove or accept for a later add.

Fixes: 9c395c1b99bd ("bpf: Add basic bpf_rb_{root,node} support")
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20260605094143.5509-1-kaitao.cheng@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpf: allow UTF-8 literals in bpf_bprintf_prepare() 2026-05-23T11:06:52+00:00 Yihan Ding dingyihan@uniontech.com 2026-04-16T12:01:41+00:00 8abad856e2a5bfc15b53a8a6420910fa73021bff [ Upstream commit b960430ea8862ef37ce53c8bf74a8dc79d3f2404 ] bpf_bprintf_prepare() only needs ASCII parsing for conversion specifiers. Plain text can safely carry bytes >= 0x80, so allow UTF-8 literals outside '%' sequences while keeping ASCII control bytes rejected and format specifiers ASCII-only. This keeps existing parsing rules for format directives unchanged, while allowing helpers such as bpf_trace_printk() to emit UTF-8 literal text. Update test_snprintf_negative() in the same commit so selftests keep matching the new plain-text vs format-specifier split during bisection. Fixes: 48cac3f4a96d ("bpf: Implement formatted output helpers with bstr_printf") Signed-off-by: Yihan Ding <dingyihan@uniontech.com> Acked-by: Paul Chaignon <paul.chaignon@gmail.com> Link: https://lore.kernel.org/r/20260416120142.1420646-2-dingyihan@uniontech.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b960430ea8862ef37ce53c8bf74a8dc79d3f2404 ]

bpf_bprintf_prepare() only needs ASCII parsing for conversion
specifiers. Plain text can safely carry bytes >= 0x80, so allow
UTF-8 literals outside '%' sequences while keeping ASCII control
bytes rejected and format specifiers ASCII-only.

This keeps existing parsing rules for format directives unchanged,
while allowing helpers such as bpf_trace_printk() to emit UTF-8
literal text.

Update test_snprintf_negative() in the same commit so selftests keep
matching the new plain-text vs format-specifier split during bisection.

Fixes: 48cac3f4a96d ("bpf: Implement formatted output helpers with bstr_printf")
Signed-off-by: Yihan Ding <dingyihan@uniontech.com>
Acked-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/20260416120142.1420646-2-dingyihan@uniontech.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpf: Fix memory access flags in helper prototypes 2026-02-26T22:59:03+00:00 Zesen Liu ftyghome@gmail.com 2026-01-20T08:28:46+00:00 fdfe75161f6e8c41a7d3023fbb815b537107b806 [ Upstream commit 802eef5afb1865bc5536a5302c068ba2215a1f72 ] After commit 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking"), the verifier started relying on the access type flags in helper function prototypes to perform memory access optimizations. Currently, several helper functions utilizing ARG_PTR_TO_MEM lack the corresponding MEM_RDONLY or MEM_WRITE flags. This omission causes the verifier to incorrectly assume that the buffer contents are unchanged across the helper call. Consequently, the verifier may optimize away subsequent reads based on this wrong assumption, leading to correctness issues. For bpf_get_stack_proto_raw_tp, the original MEM_RDONLY was incorrect since the helper writes to the buffer. Change it to ARG_PTR_TO_UNINIT_MEM which correctly indicates write access to potentially uninitialized memory. Similar issues were recently addressed for specific helpers in commit ac44dcc788b9 ("bpf: Fix verifier assumptions of bpf_d_path's output buffer") and commit 2eb7648558a7 ("bpf: Specify access type of bpf_sysctl_get_name args"). Fix these prototypes by adding the correct memory access flags. Fixes: 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking") Co-developed-by: Shuran Liu <electronlsr@gmail.com> Signed-off-by: Shuran Liu <electronlsr@gmail.com> Co-developed-by: Peili Gao <gplhust955@gmail.com> Signed-off-by: Peili Gao <gplhust955@gmail.com> Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com> Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com> Signed-off-by: Zesen Liu <ftyghome@gmail.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20260120-helper_proto-v3-1-27b0180b4e77@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 802eef5afb1865bc5536a5302c068ba2215a1f72 ]

After commit 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking"),
the verifier started relying on the access type flags in helper
function prototypes to perform memory access optimizations.

Currently, several helper functions utilizing ARG_PTR_TO_MEM lack the
corresponding MEM_RDONLY or MEM_WRITE flags. This omission causes the
verifier to incorrectly assume that the buffer contents are unchanged
across the helper call. Consequently, the verifier may optimize away
subsequent reads based on this wrong assumption, leading to correctness
issues.

For bpf_get_stack_proto_raw_tp, the original MEM_RDONLY was incorrect
since the helper writes to the buffer. Change it to ARG_PTR_TO_UNINIT_MEM
which correctly indicates write access to potentially uninitialized memory.

Similar issues were recently addressed for specific helpers in commit
ac44dcc788b9 ("bpf: Fix verifier assumptions of bpf_d_path's output buffer")
and commit 2eb7648558a7 ("bpf: Specify access type of bpf_sysctl_get_name args").

Fix these prototypes by adding the correct memory access flags.

Fixes: 37cce22dbd51 ("bpf: verifier: Refactor helper access type tracking")
Co-developed-by: Shuran Liu <electronlsr@gmail.com>
Signed-off-by: Shuran Liu <electronlsr@gmail.com>
Co-developed-by: Peili Gao <gplhust955@gmail.com>
Signed-off-by: Peili Gao <gplhust955@gmail.com>
Co-developed-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Haoran Ni <haoran.ni.cs@gmail.com>
Signed-off-by: Zesen Liu <ftyghome@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260120-helper_proto-v3-1-27b0180b4e77@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpf: Prevent nesting overflow in bpf_try_get_buffers 2025-12-18T13:03:01+00:00 Sahil Chandna chandna.sahil@gmail.com 2025-11-14T06:49:22+00:00 4a9b0581757a97ed70805bd01b3c254890020be6 [ Upstream commit c1da3df7191f1b4df9256bcd30d78f78201e1d17 ] bpf_try_get_buffers() returns one of multiple per-CPU buffers based on a per-CPU nesting counter. This mechanism expects that buffers are not endlessly acquired before being returned. migrate_disable() ensures that a task remains on the same CPU, but it does not prevent the task from being preempted by another task on that CPU. Without disabled preemption, a task may be preempted while holding a buffer, allowing another task to run on same CPU and acquire an additional buffer. Several such preemptions can cause the per-CPU nest counter to exceed MAX_BPRINTF_NEST_LEVEL and trigger the warning in bpf_try_get_buffers(). Adding preempt_disable()/preempt_enable() around buffer acquisition and release prevents this task preemption and preserves the intended bounded nesting behavior. Reported-by: syzbot+b0cff308140f79a9c4cb@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/68f6a4c8.050a0220.1be48.0011.GAE@google.com/ Fixes: 4223bf833c849 ("bpf: Remove preempt_disable in bpf_try_get_buffers") Suggested-by: Yonghong Song <yonghong.song@linux.dev> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com> Link: https://lore.kernel.org/r/20251114064922.11650-1-chandna.sahil@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c1da3df7191f1b4df9256bcd30d78f78201e1d17 ]

bpf_try_get_buffers() returns one of multiple per-CPU buffers based on a
per-CPU nesting counter. This mechanism expects that buffers are not
endlessly acquired before being returned. migrate_disable() ensures that a
task remains on the same CPU, but it does not prevent the task from being
preempted by another task on that CPU.

Without disabled preemption, a task may be preempted while holding a
buffer, allowing another task to run on same CPU and acquire an
additional buffer. Several such preemptions can cause the per-CPU
nest counter to exceed MAX_BPRINTF_NEST_LEVEL and trigger the warning in
bpf_try_get_buffers(). Adding preempt_disable()/preempt_enable() around
buffer acquisition and release prevents this task preemption and
preserves the intended bounded nesting behavior.

Reported-by: syzbot+b0cff308140f79a9c4cb@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/68f6a4c8.050a0220.1be48.0011.GAE@google.com/
Fixes: 4223bf833c849 ("bpf: Remove preempt_disable in bpf_try_get_buffers")
Suggested-by: Yonghong Song <yonghong.song@linux.dev>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
Link: https://lore.kernel.org/r/20251114064922.11650-1-chandna.sahil@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
bpf: add _impl suffix for bpf_stream_vprintk() kfunc 2025-11-05T01:50:25+00:00 Mykyta Yatsenko yatsenko@meta.com 2025-11-04T22:54:26+00:00 137cc92ffe2e71705fce112656a460d924934ebe Rename bpf_stream_vprintk() to bpf_stream_vprintk_impl(). This makes bpf_stream_vprintk() follow the already established "_impl" suffix-based naming convention for kfuncs with the bpf_prog_aux argument provided by the verifier implicitly. This convention will be taken advantage of with the upcoming KF_IMPLICIT_ARGS feature to preserve backwards compatibility to BPF programs. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20251104-implv2-v3-2-4772b9ae0e06@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev> 
Rename bpf_stream_vprintk() to bpf_stream_vprintk_impl().

This makes bpf_stream_vprintk() follow the already established "_impl"
suffix-based naming convention for kfuncs with the bpf_prog_aux
argument provided by the verifier implicitly. This convention will be
taken advantage of with the upcoming KF_IMPLICIT_ARGS feature to
preserve backwards compatibility to BPF programs.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20251104-implv2-v3-2-4772b9ae0e06@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
bpf:add _impl suffix for bpf_task_work_schedule* kfuncs 2025-11-05T01:50:25+00:00 Mykyta Yatsenko yatsenko@meta.com 2025-11-04T22:54:25+00:00 ea0714d61dea6e00b853a0116d0afe2b2fe70ef3 Rename: bpf_task_work_schedule_resume()->bpf_task_work_schedule_resume_impl() bpf_task_work_schedule_signal()->bpf_task_work_schedule_signal_impl() This aligns task work scheduling kfuncs with the established naming scheme for kfuncs with the bpf_prog_aux argument provided by the verifier implicitly. This convention will be taken advantage of with the upcoming KF_IMPLICIT_ARGS feature to preserve backwards compatibility to BPF programs. Acked-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Link: https://lore.kernel.org/r/20251104-implv2-v3-1-4772b9ae0e06@meta.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev> 
Rename:
bpf_task_work_schedule_resume()->bpf_task_work_schedule_resume_impl()
bpf_task_work_schedule_signal()->bpf_task_work_schedule_signal_impl()

This aligns task work scheduling kfuncs with the established naming
scheme for kfuncs with the bpf_prog_aux argument provided by the
verifier implicitly. This convention will be taken advantage of with the
upcoming KF_IMPLICIT_ARGS feature to preserve backwards compatibility to
BPF programs.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20251104-implv2-v3-1-4772b9ae0e06@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
bpf: Conditionally include dynptr copy kfuncs 2025-10-24T16:44:47+00:00 Malin Jonsson malin.jonsson@est.tech 2025-10-24T15:14:36+00:00 8ce93aabbf75171470e3d1be56bf1a6937dc5db8 Since commit a498ee7576de ("bpf: Implement dynptr copy kfuncs"), if CONFIG_BPF_EVENTS is not enabled, but BPF_SYSCALL and DEBUG_INFO_BTF are, the build will break like so: BTFIDS vmlinux.unstripped WARN: resolve_btfids: unresolved symbol bpf_probe_read_user_str_dynptr WARN: resolve_btfids: unresolved symbol bpf_probe_read_user_dynptr WARN: resolve_btfids: unresolved symbol bpf_probe_read_kernel_str_dynptr WARN: resolve_btfids: unresolved symbol bpf_probe_read_kernel_dynptr WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_task_str_dynptr WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_task_dynptr WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_str_dynptr WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_dynptr make[2]: *** [scripts/Makefile.vmlinux:72: vmlinux.unstripped] Error 255 make[2]: *** Deleting file 'vmlinux.unstripped' make[1]: *** [/repo/malin/upstream/linux/Makefile:1242: vmlinux] Error 2 make: *** [Makefile:248: __sub-make] Error 2 Guard these symbols with #ifdef CONFIG_BPF_EVENTS to resolve the problem. Fixes: a498ee7576de ("bpf: Implement dynptr copy kfuncs") Reported-by: Yong Gu <yong.g.gu@ericsson.com> Acked-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Malin Jonsson <malin.jonsson@est.tech> Link: https://lore.kernel.org/r/20251024151436.139131-1-malin.jonsson@est.tech Signed-off-by: Alexei Starovoitov <ast@kernel.org> 
Since commit a498ee7576de ("bpf: Implement dynptr copy kfuncs"), if
CONFIG_BPF_EVENTS is not enabled, but BPF_SYSCALL and DEBUG_INFO_BTF are,
the build will break like so:

  BTFIDS  vmlinux.unstripped
WARN: resolve_btfids: unresolved symbol bpf_probe_read_user_str_dynptr
WARN: resolve_btfids: unresolved symbol bpf_probe_read_user_dynptr
WARN: resolve_btfids: unresolved symbol bpf_probe_read_kernel_str_dynptr
WARN: resolve_btfids: unresolved symbol bpf_probe_read_kernel_dynptr
WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_task_str_dynptr
WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_task_dynptr
WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_str_dynptr
WARN: resolve_btfids: unresolved symbol bpf_copy_from_user_dynptr
make[2]: *** [scripts/Makefile.vmlinux:72: vmlinux.unstripped] Error 255
make[2]: *** Deleting file 'vmlinux.unstripped'
make[1]: *** [/repo/malin/upstream/linux/Makefile:1242: vmlinux] Error 2
make: *** [Makefile:248: __sub-make] Error 2

Guard these symbols with #ifdef CONFIG_BPF_EVENTS to resolve the problem.

Fixes: a498ee7576de ("bpf: Implement dynptr copy kfuncs")
Reported-by: Yong Gu <yong.g.gu@ericsson.com>
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Malin Jonsson <malin.jonsson@est.tech>
Link: https://lore.kernel.org/r/20251024151436.139131-1-malin.jonsson@est.tech
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf: Replace bpf_map_kmalloc_node() with kmalloc_nolock() to allocate bpf_async_cb structures. 2025-10-15T10:22:22+00:00 Alexei Starovoitov ast@kernel.org 2025-10-15T00:07:00+00:00 5fb750e8a9ae123b2034771b864b8a21dbef65cd The following kmemleak splat: [ 8.105530] kmemleak: Trying to color unknown object at 0xff11000100e918c0 as Black [ 8.106521] Call Trace: [ 8.106521] <TASK> [ 8.106521] dump_stack_lvl+0x4b/0x70 [ 8.106521] kvfree_call_rcu+0xcb/0x3b0 [ 8.106521] ? hrtimer_cancel+0x21/0x40 [ 8.106521] bpf_obj_free_fields+0x193/0x200 [ 8.106521] htab_map_update_elem+0x29c/0x410 [ 8.106521] bpf_prog_cfc8cd0f42c04044_overwrite_cb+0x47/0x4b [ 8.106521] bpf_prog_8c30cd7c4db2e963_overwrite_timer+0x65/0x86 [ 8.106521] bpf_prog_test_run_syscall+0xe1/0x2a0 happens due to the combination of features and fixes, but mainly due to commit 6d78b4473cdb ("bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()") It's using __GFP_HIGH, which instructs slub/kmemleak internals to skip kmemleak_alloc_recursive() on allocation, so subsequent kfree_rcu()-> kvfree_call_rcu()->kmemleak_ignore() complains with the above splat. To fix this imbalance, replace bpf_map_kmalloc_node() with kmalloc_nolock() and kfree_rcu() with call_rcu() + kfree_nolock() to make sure that the objects allocated with kmalloc_nolock() are freed with kfree_nolock() rather than the implicit kfree() that kfree_rcu() uses internally. Note, the kmalloc_nolock() happens under bpf_spin_lock_irqsave(), so it will always fail in PREEMPT_RT. This is not an issue at the moment, since bpf_timers are disabled in PREEMPT_RT. In the future bpf_spin_lock will be replaced with state machine similar to bpf_task_work. Fixes: 6d78b4473cdb ("bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()") Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Harry Yoo <harry.yoo@oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: linux-mm@kvack.org Link: https://lore.kernel.org/bpf/20251015000700.28988-1-alexei.starovoitov@gmail.com 
The following kmemleak splat:

[    8.105530] kmemleak: Trying to color unknown object at 0xff11000100e918c0 as Black
[    8.106521] Call Trace:
[    8.106521]  <TASK>
[    8.106521]  dump_stack_lvl+0x4b/0x70
[    8.106521]  kvfree_call_rcu+0xcb/0x3b0
[    8.106521]  ? hrtimer_cancel+0x21/0x40
[    8.106521]  bpf_obj_free_fields+0x193/0x200
[    8.106521]  htab_map_update_elem+0x29c/0x410
[    8.106521]  bpf_prog_cfc8cd0f42c04044_overwrite_cb+0x47/0x4b
[    8.106521]  bpf_prog_8c30cd7c4db2e963_overwrite_timer+0x65/0x86
[    8.106521]  bpf_prog_test_run_syscall+0xe1/0x2a0

happens due to the combination of features and fixes, but mainly due to
commit 6d78b4473cdb ("bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()")
It's using __GFP_HIGH, which instructs slub/kmemleak internals to skip
kmemleak_alloc_recursive() on allocation, so subsequent kfree_rcu()->
kvfree_call_rcu()->kmemleak_ignore() complains with the above splat.

To fix this imbalance, replace bpf_map_kmalloc_node() with
kmalloc_nolock() and kfree_rcu() with call_rcu() + kfree_nolock() to
make sure that the objects allocated with kmalloc_nolock() are freed
with kfree_nolock() rather than the implicit kfree() that kfree_rcu()
uses internally.

Note, the kmalloc_nolock() happens under bpf_spin_lock_irqsave(), so
it will always fail in PREEMPT_RT. This is not an issue at the moment,
since bpf_timers are disabled in PREEMPT_RT. In the future
bpf_spin_lock will be replaced with state machine similar to
bpf_task_work.

Fixes: 6d78b4473cdb ("bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev>
Acked-by: Harry Yoo <harry.yoo@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org
Link: https://lore.kernel.org/bpf/20251015000700.28988-1-alexei.starovoitov@gmail.com