diff options
| author | Thomas Gleixner <tglx@kernel.org> | 2026-04-28 11:10:19 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-05-01 22:32:20 +0300 |
| commit | 2cb68e45120dfc66404c7547d95b8ac6ff0b25ce (patch) | |
| tree | 9e025170945821e3c5844cfcf4e2a11ed78e1093 | |
| parent | cb48828f06afa232cc330f0f4d6be101067810b3 (diff) | |
| download | linux-2cb68e45120dfc66404c7547d95b8ac6ff0b25ce.tar.xz | |
rseq: Set rseq::cpu_id_start to 0 on unregistration
The RSEQ rework changed that to RSEQ_CPU_UNINITILIZED, which is obviously
incompatible. Revert back to the original behavior.
Fixes: 0f085b41880e ("rseq: Provide and use rseq_set_ids()")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Link: https://patch.msgid.link/20260428224427.271566313%40kernel.org
Cc: stable@vger.kernel.org
| -rw-r--r-- | kernel/rseq.c | 20 |
1 files changed, 9 insertions, 11 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index 38d3ef540760..b9f11931ef78 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -236,11 +236,6 @@ static int __init rseq_debugfs_init(void) } __initcall(rseq_debugfs_init); -static bool rseq_set_ids(struct task_struct *t, struct rseq_ids *ids, u32 node_id) -{ - return rseq_set_ids_get_csaddr(t, ids, node_id, NULL); -} - static bool rseq_handle_cs(struct task_struct *t, struct pt_regs *regs) { struct rseq __user *urseq = t->rseq.usrptr; @@ -384,19 +379,22 @@ void rseq_syscall(struct pt_regs *regs) static bool rseq_reset_ids(void) { - struct rseq_ids ids = { - .cpu_id = RSEQ_CPU_ID_UNINITIALIZED, - .mm_cid = 0, - }; + struct rseq __user *rseq = current->rseq.usrptr; /* * If this fails, terminate it because this leaves the kernel in * stupid state as exit to user space will try to fixup the ids * again. */ - if (rseq_set_ids(current, &ids, 0)) - return true; + scoped_user_rw_access(rseq, efault) { + unsafe_put_user(0, &rseq->cpu_id_start, efault); + unsafe_put_user(RSEQ_CPU_ID_UNINITIALIZED, &rseq->cpu_id, efault); + unsafe_put_user(0, &rseq->node_id, efault); + unsafe_put_user(0, &rseq->mm_cid, efault); + } + return true; +efault: force_sig(SIGSEGV); return false; } |