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uprobe: Do not emulate/sstep original instruction when ip is changed

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[ Upstream commit 4363264111 ]

If uprobe handler changes instruction pointer we still execute single
step) or emulate the original instruction and increment the (new) ip
with its length.

This makes the new instruction pointer bogus and application will
likely crash on illegal instruction execution.

If user decided to take execution elsewhere, it makes little sense
to execute the original instruction, so let's skip it.

Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20250916215301.664963-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jiri Olsa
2025-09-16 23:52:57 +02:00
committed by Greg Kroah-Hartman
parent 503ea51be2
commit 98fd1968a3
1 changed files with 7 additions and 0 deletions
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7
kernel/events/uprobes.c
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@@ -2248,6 +2248,13 @@ static void handle_swbp(struct pt_regs *regs)
handler_chain(uprobe, regs);
/*
* If user decided to take execution elsewhere, it makes little sense
* to execute the original instruction, so let's skip it.
*/
if (instruction_pointer(regs) != bp_vaddr)
goto out;
if (arch_uprobe_skip_sstep(&uprobe->arch, regs))
goto out;