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author | David S. Miller | 2020-05-15 10:57:21 -0700 |
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committer | David S. Miller | 2020-05-15 10:57:21 -0700 |
commit | 8e1381049ed5d213e7a1a7f95bbff83af8c59234 (patch) | |
tree | 25f0cead7a4ebfcbb634196ab7078ace6b74812a /Documentation | |
parent | 9a2dbb59ebd17a91f99a20b0286dfb6445981ecf (diff) | |
parent | 59df9f1fb4977b40cfad8d07b0d5baeb3a07e22c (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Alexei Starovoitov says:
====================
pull-request: bpf 2020-05-15
The following pull-request contains BPF updates for your *net* tree.
We've added 9 non-merge commits during the last 2 day(s) which contain
a total of 14 files changed, 137 insertions(+), 43 deletions(-).
The main changes are:
1) Fix secid_to_secctx LSM hook default value, from Anders.
2) Fix bug in mmap of bpf array, from Andrii.
3) Restrict bpf_probe_read to archs where they work, from Daniel.
4) Enforce returning 0 for fentry/fexit progs, from Yonghong.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/core-api/printk-formats.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 8ebe46b1af39..5dfcc4592b23 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -112,6 +112,20 @@ used when printing stack backtraces. The specifier takes into consideration the effect of compiler optimisations which may occur when tail-calls are used and marked with the noreturn GCC attribute. +Probed Pointers from BPF / tracing +---------------------------------- + +:: + + %pks kernel string + %pus user string + +The ``k`` and ``u`` specifiers are used for printing prior probed memory from +either kernel memory (k) or user memory (u). The subsequent ``s`` specifier +results in printing a string. For direct use in regular vsnprintf() the (k) +and (u) annotation is ignored, however, when used out of BPF's bpf_trace_printk(), +for example, it reads the memory it is pointing to without faulting. + Kernel Pointers --------------- |