criu/images/rseq.proto

// SPDX-License-Identifier: MIT

syntax = "proto2";

message rseq_entry {
	required uint64 rseq_abi_pointer	= 1;
	required uint32 rseq_abi_size		= 2;
	required uint32 signature		= 3;
	optional uint64 rseq_cs_pointer		= 4;
}
rseq: initial support Support basic rseq C/R scenario. Assume that: - there are no processes with IP inside the rseq critical section (CS) - kernel has ptrace(PTRACE_GET_RSEQ_CONFIGURATION) support On dump: 1. use ptrace(PTRACE_GET_RSEQ_CONFIGURATION) to get struct rseq pointer, rseq size and signature from the kernel. 2. save to the image On restore: 1. get rseq ptr, size, signature from the image 2. register it back using rseq() from the restorer parasite Fixes: #1696 Reported-by: Radostin Stoyanov <radostin@redhat.com> Suggested-by: Florian Weimer <fweimer@redhat.com> Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> 2022-04-08 23:03:37 +03:00			`// SPDX-License-Identifier: MIT`

			`syntax = "proto2";`

			`message rseq_entry {`
			`required uint64 rseq_abi_pointer = 1;`
			`required uint32 rseq_abi_size = 2;`
			`required uint32 signature = 3;`
rseq: handle rseq/rseq_cs flags properly Userspace may configure rseq cs abort policy by setting RSEQ_CS_FLAG_NO_RESTART_ON_* flags. In ("cr-dump: fixup thread IP when inside rseq cs") we have supported the case when process was caught by CRIU during rseq cs execution by fixing up IP to abort_ip. Thats a common case, but there is special flag called RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL, in this case we have to leave process IP as it was before CRIU seized it. Unfortunately, that's not all that we need here. We also must preserve (struct rseq)->rseq_cs field. You may ask like "why we need to preserve it by hands? CRIU is dumping all process memory and restores it". That's true. But not so easy. The problem here is that the kernel performs this field cleanup when it realized that the process gets out of rseq cs. But during dump/restore procedures we are executing parasite/restorer from the process context. It means that process will get out of rseq cs in any case and (struct rseq)->rseq_cs will be cleared by the kernel. So we need to restore this field by hands at the last stage of restore just before releasing processes. Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> 2022-02-22 18:22:45 +03:00			`optional uint64 rseq_cs_pointer = 4;`
rseq: initial support Support basic rseq C/R scenario. Assume that: - there are no processes with IP inside the rseq critical section (CS) - kernel has ptrace(PTRACE_GET_RSEQ_CONFIGURATION) support On dump: 1. use ptrace(PTRACE_GET_RSEQ_CONFIGURATION) to get struct rseq pointer, rseq size and signature from the kernel. 2. save to the image On restore: 1. get rseq ptr, size, signature from the image 2. register it back using rseq() from the restorer parasite Fixes: #1696 Reported-by: Radostin Stoyanov <radostin@redhat.com> Suggested-by: Florian Weimer <fweimer@redhat.com> Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> 2022-04-08 23:03:37 +03:00			`}`