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bpf: Unbreak BPF_PROG_TYPE_KPROBE when kprobe is called via do_int3

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[ Upstream commit 548f1191d86ccb9bde2a5305988877b7584c01eb ]

The commit 0d00449c7a ("x86: Replace ist_enter() with nmi_enter()")
converted do_int3 handler to be "NMI-like".
That made old if (in_nmi()) check abort execution of bpf programs
attached to kprobe when kprobe is firing via int3
(For example when kprobe is placed in the middle of the function).
Remove the check to restore user visible behavior.

Fixes: 0d00449c7a ("x86: Replace ist_enter() with nmi_enter()")
Reported-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/bpf/20210203070636.70926-1-alexei.starovoitov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Alexei Starovoitov 2021-02-02 23:06:36 -08:00 committed by Greg Kroah-Hartman
parent 40e3b5c128
commit 52d29b4783
1 changed files with 0 additions and 3 deletions
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3
kernel/trace/bpf_trace.c
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@ -93,9 +93,6 @@ unsigned int trace_call_bpf(struct trace_event_call *call, void *ctx)
{ {
unsigned int ret; unsigned int ret;
if (in_nmi()) /* not supported yet */
return 1;
cant_sleep(); cant_sleep();
if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) { if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1)) {