Re: Re: [PATCH v2 0/2] Fix failure to access u32* argument of tracked function

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



在 2023/4/7 18:49, Feng Zhou 写道:
在 2023/4/7 17:33, Jiri Olsa 写道:
On Fri, Apr 07, 2023 at 04:46:06PM +0800, Feng zhou wrote:
From: Feng Zhou<zhoufeng.zf@xxxxxxxxxxxxx>

When access traced function arguments with type is u32*, bpf verifier failed. Because u32 have typedef, needs to skip modifier. Add btf_type_is_modifier in
is_int_ptr. Add a selftest to check it.

Feng Zhou (2):
   bpf/btf: Fix is_int_ptr()
   selftests/bpf: Add test to access u32 ptr argument in tracing program
hi,
it breaks several tests in test_progs suite:

#11/36   bpf_iter/link-iter:FAIL
#11      bpf_iter:FAIL
test_dummy_st_ops_attach:FAIL:dummy_st_ops_load unexpected error: -13
#63/1    dummy_st_ops/dummy_st_ops_attach:FAIL
test_dummy_init_ret_value:FAIL:dummy_st_ops_load unexpected error: -13
#63/2    dummy_st_ops/dummy_init_ret_value:FAIL
test_dummy_init_ptr_arg:FAIL:dummy_st_ops_load unexpected error: -13
#63/3    dummy_st_ops/dummy_init_ptr_arg:FAIL
test_dummy_multiple_args:FAIL:dummy_st_ops_load unexpected error: -13
#63/4    dummy_st_ops/dummy_multiple_args:FAIL
test_dummy_sleepable:FAIL:dummy_st_ops_load unexpected error: -13
#63/5    dummy_st_ops/dummy_sleepable:FAIL
#63      dummy_st_ops:FAIL
test_fentry_fexit:FAIL:fentry_skel_load unexpected error: -13
#69      fentry_fexit:FAIL
test_fentry_test:FAIL:fentry_skel_load unexpected error: -13
#70      fentry_test:FAIL

jirka


I tried it, and it did cause the test to fail. Bpfverify reported an error,
'R1 invalid mem access'scalar', let me confirm the reason.

I used btf_type_skip_modifiers,but did not delete
the previous "t = btf_type_by_id (btf, t- > type);"
resulting in some testcases failing. I will send a
v3 nextweek, thank you for your suggestion.


Changelog:
v1->v2: Addressed comments from Martin KaFai Lau
- Add a selftest.
- use btf_type_skip_modifiers.
Some details in here:
https://lore.kernel.org/all/20221012125815.76120-1-zhouchengming@xxxxxxxxxxxxx/

  kernel/bpf/btf.c                                    |  5 ++---
  net/bpf/test_run.c                                  |  8 +++++++-
  .../testing/selftests/bpf/verifier/btf_ctx_access.c | 13 +++++++++++++
  3 files changed, 22 insertions(+), 4 deletions(-)

--
2.20.1






[Index of Archives]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]

  Powered by Linux