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| author | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2018-10-09 23:40:09 +0200 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2018-10-28 13:41:51 +0100 |
| commit | 5c81be53407434ce22b849722a3d691295480016 (patch) | |
| tree | 930f36f9263b5d02c176d6b13b0ed5a762c8fd83 /hurd | |
| parent | 2d0d1d38761cd9aeb7063c5cce1993cec909f67f (diff) | |
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hurd: Fix race between calling RPC and handling a signal
* sysdeps/mach/hurd/i386/intr-msg.h (INTR_MSG_TRAP): Make
_hurd_intr_rpc_msg_about_to global point to start of controlled
assembly snippet. Make it check canceled flag.
* hurd/hurdsig.c (_hurdsig_abort_rpcs): Only mutate thread if it passed
the _hurd_intr_rpc_msg_about_to point.
* hurd/intr-msg.c (_hurd_intr_rpc_mach_msg): Remove comment on mutation
issue, remove cancel flag check.
Diffstat (limited to 'hurd')
| -rw-r--r-- | hurd/hurdsig.c | 4 | ||||
| -rw-r--r-- | hurd/intr-msg.c | 17 |
2 files changed, 5 insertions, 16 deletions
diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c index 48179b4197..d105615e42 100644 --- a/hurd/hurdsig.c +++ b/hurd/hurdsig.c @@ -292,6 +292,7 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread, struct machine_thread_all_state *state, int *state_change, void (*reply) (void)) { + extern const void _hurd_intr_rpc_msg_about_to; extern const void _hurd_intr_rpc_msg_in_trap; mach_port_t rcv_port = MACH_PORT_NULL; mach_port_t intr_port; @@ -307,7 +308,8 @@ _hurdsig_abort_rpcs (struct hurd_sigstate *ss, int signo, int sigthread, receive completes immediately or aborts. */ abort_thread (ss, state, reply); - if (state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap) + if (state->basic.PC >= (natural_t) &_hurd_intr_rpc_msg_about_to && + state->basic.PC < (natural_t) &_hurd_intr_rpc_msg_in_trap) { /* The thread is about to do the RPC, but hasn't yet entered mach_msg. Mutate the thread's state so it knows not to try diff --git a/hurd/intr-msg.c b/hurd/intr-msg.c index 1f7724ee8b..7ace0a16b3 100644 --- a/hurd/intr-msg.c +++ b/hurd/intr-msg.c @@ -114,23 +114,10 @@ _hurd_intr_rpc_mach_msg (mach_msg_header_t *msg, message: - /* XXX - At all points here (once SS->intr_port is set), the signal thread - thinks we are "about to enter the syscall", and might mutate our - return-value register. This is bogus. - */ - - if (ss->cancel) - { - /* We have been cancelled. Don't do an RPC at all. */ - ss->intr_port = MACH_PORT_NULL; - ss->cancel = 0; - return EINTR; - } - /* Note that the signal trampoline code might modify our OPTION! */ err = INTR_MSG_TRAP (msg, option, send_size, - rcv_size, rcv_name, timeout, notify); + rcv_size, rcv_name, timeout, notify, + &ss->cancel, &ss->intr_port); switch (err) { |