fusefs: fix another semi-infinite loop bug regarding signal handling
fticket_wait_answer would spin if it received an unhandled signal whose default disposition is to terminate. The reason is because msleep(9) would return EINTR even for a masked signal. One reason is when the thread is stopped, which happens for example during sigexit(). Fix this bug by returning immediately if fticket_wait_answer ever gets interrupted a second time, for any reason. Sponsored by: The FreeBSD Foundation
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parent
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commit
f05962453e
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/projects/fuse2/; revision=350113
@ -439,11 +439,12 @@ fticket_wait_answer(struct fuse_ticket *ftick)
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sigset_t blockedset, oldset;
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int err = 0, stops_deferred;
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struct fuse_data *data;
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bool interrupted = false;
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if (fsess_isimpl(ftick->tk_data->mp, FUSE_INTERRUPT)) {
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SIGEMPTYSET(blockedset);
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} else {
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/* May as well block all signals */
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/* Block all signals except (implicitly) SIGKILL */
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SIGFILLSET(blockedset);
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}
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stops_deferred = sigdeferstop(SIGDEFERSTOP_SILENT);
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@ -489,7 +490,6 @@ fticket_wait_answer(struct fuse_ticket *ftick)
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* or EAGAIN to the interrupt.
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*/
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sigset_t tmpset;
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int sig;
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SDT_PROBE2(fusefs, , ipc, trace, 4,
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"fticket_wait_answer: interrupt");
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@ -498,22 +498,28 @@ fticket_wait_answer(struct fuse_ticket *ftick)
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PROC_LOCK(td->td_proc);
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mtx_lock(&td->td_proc->p_sigacts->ps_mtx);
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sig = cursig(td);
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tmpset = td->td_proc->p_siglist;
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SIGSETOR(tmpset, td->td_siglist);
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mtx_unlock(&td->td_proc->p_sigacts->ps_mtx);
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PROC_UNLOCK(td->td_proc);
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fuse_lck_mtx_lock(ftick->tk_aw_mtx);
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if (!SIGISMEMBER(tmpset, SIGKILL)) {
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if (!interrupted && !SIGISMEMBER(tmpset, SIGKILL)) {
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/*
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* Block the just-delivered signal while we wait for an
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* interrupt response
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* Block all signals while we wait for an interrupt
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* response. The protocol doesn't discriminate between
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* different signals.
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*/
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SIGADDSET(blockedset, sig);
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SIGFILLSET(blockedset);
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interrupted = true;
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goto retry;
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} else {
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/* Return immediately for fatal signals */
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/*
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* Return immediately for fatal signals, or if this is
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* the second interruption. We should only be
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* interrupted twice if the thread is stopped, for
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* example during sigexit.
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*/
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}
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} else if (err) {
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SDT_PROBE2(fusefs, , ipc, trace, 6,
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