* [PATCH] s390/uprobes: Fix off-by-one bug in emulated PER handling
@ 2026-10-09 13:26 Heiko Carstens
2026-10-12 7:05 ` Sven Schnelle
0 siblings, 1 reply; 2+ messages in thread
From: Heiko Carstens @ 2026-10-09 13:26 UTC (permalink / raw)
To: Alexander Gordeev, Sven Schnelle, Vasily Gorbik, Christian Borntraeger
Cc: linux-kernel, linux-s390
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] s390/uprobes: Fix off-by-one bug in emulated PER handling
2026-10-09 13:26 [PATCH] s390/uprobes: Fix off-by-one bug in emulated PER handling Heiko Carstens
@ 2026-10-12 7:05 ` Sven Schnelle
0 siblings, 0 replies; 2+ messages in thread
From: Sven Schnelle @ 2026-10-12 7:05 UTC (permalink / raw)
To: Heiko Carstens
Cc: Alexander Gordeev, Vasily Gorbik, Christian Borntraeger,
linux-kernel, linux-s390
Heiko Carstens <hca@linux.ibm.com> writes:
> 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;
Reviewed-by: Sven Schnelle <svens@linux.ibm.com>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-10-12 7:05 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-10-09 13:26 [PATCH] s390/uprobes: Fix off-by-one bug in emulated PER handling Heiko Carstens
2026-10-12 7:05 ` Sven Schnelle
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®