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authorLinus Torvalds <torvalds@linux-foundation.org>2020-05-15 13:10:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-05-15 13:10:06 -0700
commitf85c1598ddfe83f61d0656bd1d2025fa3b148b99 (patch)
tree8eb85a90ecaa578f9a994f269a5e094f619f240a /Documentation
parentd5dfe4f1b44ed532653c2335267ad9599c8a698e (diff)
parent8e1381049ed5d213e7a1a7f95bbff83af8c59234 (diff)
downloadlinux-f85c1598ddfe83f61d0656bd1d2025fa3b148b99.tar.bz2
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from David Miller: 1) Fix sk_psock reference count leak on receive, from Xiyu Yang. 2) CONFIG_HNS should be invisible, from Geert Uytterhoeven. 3) Don't allow locking route MTUs in ipv6, RFCs actually forbid this, from Maciej Żenczykowski. 4) ipv4 route redirect backoff wasn't actually enforced, from Paolo Abeni. 5) Fix netprio cgroup v2 leak, from Zefan Li. 6) Fix infinite loop on rmmod in conntrack, from Florian Westphal. 7) Fix tcp SO_RCVLOWAT hangs, from Eric Dumazet. 8) Various bpf probe handling fixes, from Daniel Borkmann. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (68 commits) selftests: mptcp: pm: rm the right tmp file dpaa2-eth: properly handle buffer size restrictions bpf: Restrict bpf_trace_printk()'s %s usage and add %pks, %pus specifier bpf: Add bpf_probe_read_{user, kernel}_str() to do_refine_retval_range bpf: Restrict bpf_probe_read{, str}() only to archs where they work MAINTAINERS: Mark networking drivers as Maintained. ipmr: Add lockdep expression to ipmr_for_each_table macro ipmr: Fix RCU list debugging warning drivers: net: hamradio: Fix suspicious RCU usage warning in bpqether.c net: phy: broadcom: fix BCM54XX_SHD_SCR3_TRDDAPD value for BCM54810 tcp: fix error recovery in tcp_zerocopy_receive() MAINTAINERS: Add Jakub to networking drivers. MAINTAINERS: another add of Karsten Graul for S390 networking drivers: ipa: fix typos for ipa_smp2p structure doc pppoe: only process PADT targeted at local interfaces selftests/bpf: Enforce returning 0 for fentry/fexit programs bpf: Enforce returning 0 for fentry/fexit progs net: stmmac: fix num_por initialization security: Fix the default value of secid_to_secctx hook libbpf: Fix register naming in PT_REGS s390 macros ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/core-api/printk-formats.rst14
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
---------------