5.4-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Olsa jolsa@kernel.org
[ Upstream commit 4363264111e1297fa37aa39b0598faa19298ecca ]
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 --- kernel/events/uprobes.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 6285674412f25..2b809bc849dd6 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -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;