Commit 056de1e8 authored by Marc-André Lureau's avatar Marc-André Lureau Committed by Eduardo Otubo
Browse files

seccomp: allow sched_setscheduler() with SCHED_IDLE policy 

Current and upcoming mesa releases rely on a shader disk cash. It uses
a thread job queue with low priority, set with
sched_setscheduler(SCHED_IDLE). However, that syscall is rejected by
the "resourcecontrol" seccomp qemu filter.

Since it should be safe to allow lowering thread priority, let's allow
scheduling thread to idle policy.

Related to:
https://bugzilla.redhat.com/show_bug.cgi?id=1594456



Signed-off-by: default avatarMarc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: default avatarEduardo Otubo <otubo@redhat.com>
parent c447afd5

qemu-seccomp.c

+10 −2
Original line number Diff line number Diff line
@@ -34,6 +34,12 @@ 
struct QemuSeccompSyscall {

    int32_t num;

    uint8_t set;

    uint8_t narg;

    const struct scmp_arg_cmp *arg_cmp;

};



const struct scmp_arg_cmp sched_setscheduler_arg[] = {

    SCMP_A1(SCMP_CMP_NE, SCHED_IDLE)

};



static const struct QemuSeccompSyscall blacklist[] = {
@@ -92,7 +98,8 @@ static const struct QemuSeccompSyscall blacklist[] = { 
    { SCMP_SYS(setpriority),            QEMU_SECCOMP_SET_RESOURCECTL },

    { SCMP_SYS(sched_setparam),         QEMU_SECCOMP_SET_RESOURCECTL },

    { SCMP_SYS(sched_getparam),         QEMU_SECCOMP_SET_RESOURCECTL },

    { SCMP_SYS(sched_setscheduler),     QEMU_SECCOMP_SET_RESOURCECTL },

    { SCMP_SYS(sched_setscheduler),     QEMU_SECCOMP_SET_RESOURCECTL,

      ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },

    { SCMP_SYS(sched_getscheduler),     QEMU_SECCOMP_SET_RESOURCECTL },

    { SCMP_SYS(sched_setaffinity),      QEMU_SECCOMP_SET_RESOURCECTL },

    { SCMP_SYS(sched_getaffinity),      QEMU_SECCOMP_SET_RESOURCECTL },
@@ -118,7 +125,8 @@ static int seccomp_start(uint32_t seccomp_opts) 
            continue;

        }



        rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);

        rc = seccomp_rule_add_array(ctx, SCMP_ACT_KILL, blacklist[i].num,

                                    blacklist[i].narg, blacklist[i].arg_cmp);

        if (rc < 0) {

            goto seccomp_return;

        }