From: Jiri Olsa Date: Tue, 16 Sep 2025 21:52:57 +0000 (+0200) Subject: uprobe: Do not emulate/sstep original instruction when ip is changed X-Git-Tag: v6.17.8~643 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f745f315be69c5b27c813b6d4172f8c8ee09ecf7;p=thirdparty%2Fkernel%2Fstable.git uprobe: Do not emulate/sstep original instruction when ip is changed [ 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 Acked-by: Andrii Nakryiko Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20250916215301.664963-3-jolsa@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 4b97d16f731c1..109276c68ecba 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -2741,6 +2741,13 @@ 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;