Namhyung Kim 90805175a2 bpf: Adjust BPF stack helper functions to accommodate skip > 0 ... commit ee2a098851 upstream. Let's say that the caller has storage for num_elem stack frames. Then, the BPF stack helper functions walk the stack for only num_elem frames. This means that if skip > 0, one keeps only 'num_elem - skip' frames. This is because it sets init_nr in the perf_callchain_entry to the end of the buffer to save num_elem entries only. I believe it was because the perf callchain code unwound the stack frames until it reached the global max size (sysctl_perf_event_max_stack). However it now has perf_callchain_entry_ctx.max_stack to limit the iteration locally. This simplifies the code to handle init_nr in the BPF callstack entries and removes the confusion with the perf_event's __PERF_SAMPLE_CALLCHAIN_EARLY which sets init_nr to 0. Also change the comment on bpf_get_stack() in the header file to be more explicit what the return value means. Fixes: c195651e56 ("bpf: add bpf_get_stack helper") Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/30a7b5d5-6726-1cc2-eaee-8da2828a9a9c@oracle.com Link: https://lore.kernel.org/bpf/20220314182042.71025-1-namhyung@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Based-on-patch-by: Eugene Loh <eugene.loh@oracle.com>		2022-04-08 14:40:43 +02:00
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asm-generic	aio: fix use-after-free due to missing POLLFREE handling	2021-12-14 11:32:40 +01:00
drm	drm/fourcc: fix Amlogic format modifier masks	2021-03-04 11:37:38 +01:00
linux	bpf: Adjust BPF stack helper functions to accommodate skip > 0	2022-04-08 14:40:43 +02:00
misc	habanalabs: Add an option to map CB to device MMU	2020-09-22 18:49:54 +03:00
mtd	MTD: mtd-abi.h: drop a duplicated word	2020-08-02 23:00:10 +02:00
rdma	RDMA/vmw_pvrdma: Fix network_hdr_type reported in WC	2021-01-30 13:55:18 +01:00
scsi	scsi: qla2xxx: Change in PUREX to handle FPIN ELS requests	2020-07-01 22:24:16 -04:00
sound	ALSA: fix kernel-doc markups	2020-10-26 15:26:31 +01:00
video
xen	xen/gntdev: gntdev.h: drop a duplicated word	2020-08-03 07:46:42 +02:00
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