shaba/systemd-stable
1
1
Fork 0
mirror of https://github.com/systemd/systemd-stable.git synced 2024-12-21 09:33:57 +03:00
Code

sd-event: always initialize sd_event.perturb

Browse Source 
If the boot ID cannot be obtained, let's first fallback to the machine
ID, and if still cannot, then let's use 0.
Otherwise, no timer event source cannot be triggered.

Fixes #26549.
This commit is contained in:
Yu Watanabe 2023-02-23 07:31:01 +09:00
parent a954b2492e
commit 6d2326e036
1 changed files with 10 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
src/libsystemd/sd-event/sd-event.c
View File

@ -1258,22 +1258,21 @@ _public_ int sd_event_add_io(
}
static void initialize_perturb(sd_event *e) {
sd_id128_t bootid = {};
sd_id128_t id = {};
/* When we sleep for longer, we try to realign the wakeup to
the same time within each minute/second/250ms, so that
events all across the system can be coalesced into a single
CPU wakeup. However, let's take some system-specific
randomness for this value, so that in a network of systems
with synced clocks timer events are distributed a
bit. Here, we calculate a perturbation usec offset from the
boot ID. */
/* When we sleep for longer, we try to realign the wakeup to the same time within each
* minute/second/250ms, so that events all across the system can be coalesced into a single CPU
* wakeup. However, let's take some system-specific randomness for this value, so that in a network
* of systems with synced clocks timer events are distributed a bit. Here, we calculate a
* perturbation usec offset from the boot ID (or machine ID if failed, e.g. /proc is not mounted). */
if (_likely_(e->perturb != USEC_INFINITY))
return;
if (sd_id128_get_boot(&bootid) >= 0)
e->perturb = (bootid.qwords[0] ^ bootid.qwords[1]) % USEC_PER_MINUTE;
if (sd_id128_get_boot(&id) >= 0 || sd_id128_get_machine(&id) > 0)
e->perturb = (id.qwords[0] ^ id.qwords[1]) % USEC_PER_MINUTE;
else
e->perturb = 0; /* This is a super early process without /proc and /etc ?? */
}
static int event_setup_timer_fd(