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| author | Alexei Starovoitov <ast@kernel.org> | 2026-11-01 19:05:11 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-11-02 00:10:39 +0000 |
| commit | ca580b034380fa9a69cc973637d1859ec4f5b344 (patch) | |
| tree | 137fab0af2917ba3c8544d8c00c89b0a8f7c9b92 /tools/perf/scripts/python/event_analyzing_sample.py | |
| parent | a08ba2ab79dffd92c32d3f2dadfc7eba03625a2b (diff) | |
bpf: Refuse to map an arena at address 0
The first mmap() of an arena sets user_vm_start and user_vm_end. Each
subsequent mmap() must use the same range. The value 0 in user_vm_start
means that the range is not set, but a mapping can start at address 0. Then
arena_map_mmap() does not check vm_start and sets user_vm_start again. The
range tree counts pages from user_vm_start. With a new user_vm_start it
reports allocated pages as free, and apply_range_set_cb() fails with
-EBUSY.
An arena at address 0 is not useful, because the verifier rejects all progs
that refer to it. Return -EINVAL from arena_get_unmapped_area(). It runs
before mmap() removes the old mappings in the range.
Fixes: 317460317a02 ("bpf: Introduce bpf_arena.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://patch.msgid.link/20261101190535.1454146-4-alexei.starovoitov@gmail.com
Diffstat (limited to 'tools/perf/scripts/python/event_analyzing_sample.py')
0 files changed, 0 insertions, 0 deletions