Merge branch 'bpf-fix-sleepable-check-for-tracing-lsm-prog'

Leon Hwang says:

====================
bpf: Fix sleepable check for tracing/lsm prog

When CONFIG_FUNCTION_ERROR_INJECTION is disabled, a sleepable tracing prog
is allowed to attach to '__x64_'-alike prefix symbols.

It is because the verifier does not verify whether the symbol is a kernel
function or a bpf prog. That said, a sleepable tracing prog is allowed to
attach to a bpf prog target whose name has '__x64_'-alike prefix.

For example, a sleepable fentry prog attaches to a '__x64_sys_nop' XDP
prog, and copies buffer from a user pointer with bpf_copy_from_user()
helper. After attaching the XDP prog to lo interface, the kernel BUG
could be triggered by 'ping -c 1 -W 1 127.0.0.1':

[    3.460756] BUG: sleeping function called from invalid context at kernel/bpf/trampoline.c:1324

Fix it by disallowing sleepable prog always when its target
btf is not kernel's btf.

Changes:
v3 -> v4:
* Move btf check outside of 'switch (prog->type)'. (per Andrii)
* v3: https://lore.kernel.org/bpf/20260804145710.43062-1-leon.hwang@linux.dev/

v2 -> v3:
* Use btf_is_kernel() instead of passing 'tgt_prog'. (per Andrii)
* v2: https://lore.kernel.org/bpf/20260725132624.78373-1-leon.hwang@linux.dev/

v1 -> v2:
* Drop redundant 'prog->sleepable' check. (per Viktor)
* Collect Acked-by from Viktor, Thanks.
* v1: https://lore.kernel.org/bpf/20260724141422.10463-1-leon.hwang@linux.dev/
====================

Link: https://patch.msgid.link/20260805150810.34907-1-leon.hwang@linux.dev
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

0 files changed, 0 insertions, 0 deletions