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| author | Song Liu <songliubraving@fb.com> | 2019-01-08 14:20:44 -0800 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-01-10 16:02:17 +0100 |
| commit | beaf3d1901f4ea46fbd5c9d857227d99751de469 (patch) | |
| tree | f02f6f124dbc337ec1a556ddea4e1907fc556515 | |
| parent | f98937c6bb73ae11717a15aec85c187d33ca5d34 (diff) | |
| download | linux-beaf3d1901f4ea46fbd5c9d857227d99751de469.tar.bz2 | |
bpf: fix panic in stack_map_get_build_id() on i386 and arm32
As Naresh reported, test_stacktrace_build_id() causes panic on i386 and
arm32 systems. This is caused by page_address() returns NULL in certain
cases.
This patch fixes this error by using kmap_atomic/kunmap_atomic instead
of page_address.
Fixes: 615755a77b24 (" bpf: extend stackmap to save binary_build_id+offset instead of address")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | kernel/bpf/stackmap.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 90daf285de03..d9e2483669d0 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -260,7 +260,7 @@ static int stack_map_get_build_id(struct vm_area_struct *vma, return -EFAULT; /* page not mapped */ ret = -EINVAL; - page_addr = page_address(page); + page_addr = kmap_atomic(page); ehdr = (Elf32_Ehdr *)page_addr; /* compare magic x7f "ELF" */ @@ -276,6 +276,7 @@ static int stack_map_get_build_id(struct vm_area_struct *vma, else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64) ret = stack_map_get_build_id_64(page_addr, build_id); out: + kunmap_atomic(page_addr); put_page(page); return ret; } |