linux/samples
Jesper Dangaard Brouer 7bc57950bd samples/bpf: bpf_load.c order of prog_fd[] should correspond with ELF order
An eBPF ELF file generated with LLVM can contain several program
section, which can be used for bpf tail calls.  The bpf prog file
descriptors are accessible via array prog_fd[].

At-least XDP samples assume ordering, and uses prog_fd[0] is the main
XDP program to attach.  The actual order of array prog_fd[] depend on
whether or not a bpf program section is referencing any maps or not.
Not using a map result in being loaded/processed after all other
prog section.  Thus, this can lead to some very strange and hard to
debug situation, as the user can only see a FD and cannot correlated
that with the ELF section name.

The fix is rather simple, and even removes duplicate memcmp code.
Simply load program sections as the last step, instead of
load_and_attach while processing the relocation section.

When working with tail calls, it become even more essential that the
order of prog_fd[] is consistant, like the current dependency of the
map_fd[] order.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-31 12:59:20 -04:00
..
auxdisplay
blackfin
bpf samples/bpf: bpf_load.c order of prog_fd[] should correspond with ELF order 2017-05-31 12:59:20 -04:00
configfs
connector make use of make variable CURDIR instead of calling pwd 2016-12-11 12:12:56 +01:00
hidraw
hw_breakpoint
kdb
kfifo
kobject
kprobes
livepatch livepatch: allow removal of a disabled patch 2017-03-08 09:38:43 +01:00
mei mei: drop the TODO from samples 2017-04-26 11:38:56 +02:00
mic/mpssd
pktgen
rpmsg
seccomp samples/seccomp: fix 64-bit comparison macros 2017-01-09 17:22:03 +11:00
statx statx: Include a mask for stx_attributes in struct statx 2017-04-03 01:06:00 -04:00
timers
trace_events sched/core: Remove the tsk_cpus_allowed() wrapper 2017-03-02 08:42:24 +01:00
trace_printk
uhid
v4l
vfio-mdev vfio-mdev: remove some dead code 2017-01-11 12:12:37 -07:00
watchdog
Kconfig statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00
Makefile statx: Add a system call to make enhanced file info available 2017-03-02 20:51:15 -05:00