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| author |  Alexei Starovoitov <ast@kernel.org>
| 2020-08-31 13:16:51 -0700 |
|---|---|---|
| committer |  Daniel Borkmann <daniel@iogearbox.net>
| 2020-08-31 23:03:57 +0200 |
| commit | f56407fa6e69499a06bf1e0543fa93be6922acba (patch) | |
| tree | 4bee8de2bdfd2f3caa3c4499c54b9196129c6525 /kernel | |
| parent | samples/bpf: Fix to xdpsock to avoid recycling frames (diff) | |
| download | linux-f56407fa6e69499a06bf1e0543fa93be6922acba.tar.gz linux-f56407fa6e69499a06bf1e0543fa93be6922acba.tar.bz2 linux-f56407fa6e69499a06bf1e0543fa93be6922acba.zip | |
bpf: Remove bpf_lsm_file_mprotect from sleepable list.
Technically the bpf programs can sleep while attached to bpf_lsm_file_mprotect,
but such programs need to access user memory. So they're in might_fault()
category. Which means they cannot be called from file_mprotect lsm hook that
takes write lock on mm->mmap_lock.
Adjust the test accordingly.
Also add might_fault() to __bpf_prog_enter_sleepable() to catch such deadlocks early.
Fixes: 1e6c62a88215 ("bpf: Introduce sleepable BPF programs")
Fixes: e68a144547fc ("selftests/bpf: Add sleepable tests")
Reported-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200831201651.82447-1-alexei.starovoitov@gmail.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/trampoline.c | 1 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 1 |
2 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index c2b76545153c..7dd523a7e32d 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -409,6 +409,7 @@ void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start) void notrace __bpf_prog_enter_sleepable(void) { rcu_read_lock_trace(); + might_fault(); } void notrace __bpf_prog_exit_sleepable(void) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b4c22b5ce5a2..b4e9c56b8b32 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -11006,7 +11006,6 @@ static int check_attach_modify_return(struct bpf_prog *prog, unsigned long addr) /* non exhaustive list of sleepable bpf_lsm_*() functions */ BTF_SET_START(btf_sleepable_lsm_hooks) #ifdef CONFIG_BPF_LSM -BTF_ID(func, bpf_lsm_file_mprotect) BTF_ID(func, bpf_lsm_bprm_committed_creds) #else BTF_ID_UNUSED |