From: Heiko Carstens <hca@linux.ibm.com>
To: Alexander Gordeev <agordeev@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org
Subject: [PATCH] s390/uprobes: Fix off-by-one bug in emulated PER handling
Date: Fri, 9 Oct 2026 15:26:04 +0200 [thread overview]
Message-ID: <20261009132604.2434271-1-hca@linux.ibm.com> (raw)
The uprobes code emulates some instructions, and with that also
PER storage-alteration handling, in case a debugger is attached.
The PER storage-alteration handling contains an off-by-one bug, which
may lead to PER traps which should not happen. Adjust the comparison
in sim_stor_event() to fix that.
Fixes: 8d1a2427d8fc ("s390/uprobes: fix user space PER events")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
arch/s390/kernel/uprobes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/kernel/uprobes.c b/arch/s390/kernel/uprobes.c
index c624f3361e43..b2b8a377ced6 100644
--- a/arch/s390/kernel/uprobes.c
+++ b/arch/s390/kernel/uprobes.c
@@ -241,7 +241,7 @@ static void sim_stor_event(struct pt_regs *regs, void *addr, int len)
return;
if (!(current->thread.per_user.control & PER_EVENT_STORE))
return;
- if ((void *)current->thread.per_user.start > (addr + len))
+ if ((void *)current->thread.per_user.start > (addr + len - 1))
return;
if ((void *)current->thread.per_user.end < addr)
return;
--
2.53.0
reply other threads:[~2026-10-09 13:26 UTC|newest]
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