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Description of problem:
In RHEL 8 the hrtimer_cpu_base struct now contains 8 hrtimer_clock_base ‘s and crash timer cmd does not account for them. It needs to be updated.
Crash version:
Crash 7.3.1++
GNU gdb (GDB) 7.6
crash> hrtimer_cpu_base
struct hrtimer_cpu_base {
raw_spinlock_t lock;
unsigned int cpu;
unsigned int active_bases;
unsigned int clock_was_set_seq;
unsigned int hres_active : 1;
unsigned int in_hrtirq : 1;
unsigned int hang_detected : 1;
unsigned int softirq_activated : 1;
unsigned int nr_events;
unsigned short nr_retries;
unsigned short nr_hangs;
unsigned int max_hang_time;
spinlock_t softirq_expiry_lock;
atomic_t timer_waiters;
ktime_t expires_next;
struct hrtimer *next_timer;
ktime_t softirq_expires_next;
struct hrtimer *softirq_next_timer;
struct hrtimer_clock_base clock_base[8]; <----
}
SIZE: 0x480
crash>
Version-Release number of selected component (if applicable):
Crash version:
Crash 7.3.1++
GNU gdb (GDB) 7.6
How reproducible:
always.
Steps to Reproduce:
1.run crash on a rhel8 dump.
2.
3.
Actual results:
Expected results:
Additional info:
Example from dump:
Dump files:
KERNEL: /cores/retrace/repos/kernel/x86_64/usr/lib/debug/lib/modules/4.18.0-305.19.1.rt7.91.el8_4.x86_64/vmlinux [TAINTED]
DUMPFILE: /cores/retrace/tasks/510256984/crash/vmcore [PARTIAL DUMP]
Timer cmd:
crash> timer -r -C 11
CPU: 11 HRTIMER_CPU_BASE: ffff8f829f95ee00
CLOCK: 0 HRTIMER_CLOCK_BASE: ffff8f829f95ee80 [ktime_get]
(empty)
CLOCK: 1 HRTIMER_CLOCK_BASE: ffff8f829f95ef00 [ktime_get_real]
(empty)
CLOCK: 2 HRTIMER_CLOCK_BASE: ffff8f829f95ef80 [ktime_get_boottime]
(empty)
crash>
In this dump we are actually waiting for a timer on CPU 11 clock 4 to be run.
I hard coded the clocks to show all 8 of them.
Same dump:
crash-vl> sys
KERNEL: /cores/retrace/repos/kernel/x86_64/usr/lib/debug/lib/modules/4.18.0-305.19.1.rt7.91.el8_4.x86_64/vmlinux
DUMPFILE: /cores/retrace/tasks/510256984/crash/vmcore [PARTIAL DUMP]
Now you can see the timers we are waiting on clock 4 and 5.
crash-vl> timer -r -C 11
CPU: 11 HRTIMER_CPU_BASE: ffff9a775f95ee00
CLOCK: 0 HRTIMER_CLOCK_BASE: ffff9a775f95ee80 [ktime_get]
(empty)
CLOCK: 1 HRTIMER_CLOCK_BASE: ffff9a775f95ef00 [ktime_get_real]
(empty)
CLOCK: 2 HRTIMER_CLOCK_BASE: ffff9a775f95ef80 [ktime_get_boottime]
(empty)
CLOCK: 3 HRTIMER_CLOCK_BASE: ffff9a775f95f000 [ktime_get_clocktai]
(empty)
CLOCK: 4 HRTIMER_CLOCK_BASE: ffff9a775f95f080 [ktime_get]
CURRENT
48114047000000
SOFTEXPIRES EXPIRES TTE HRTIMER FUNCTION
48048203002814 48048203052814 -65843947186 ffffae5889f67e78 ffffffff96770fa0 <hrtimer_wakeup>
CLOCK: 5 HRTIMER_CLOCK_BASE: ffff9a775f95f100 [ktime_get_real]
CURRENT
1640021151290259551
SOFTEXPIRES EXPIRES TTE HRTIMER FUNCTION
1640021064148260307 1640021064148310307 -87141949244 ffffae588a9c7d30 ffffffff96770fa0 <hrtimer_wakeup>
CLOCK: 6 HRTIMER_CLOCK_BASE: ffff9a775f95f180 [ktime_get_boottime]
(empty)
CLOCK: 7 HRTIMER_CLOCK_BASE: ffff9a775f95f200 [ktime_get_clocktai]
(empty)
crash-vl>
The real issue in the dump is that they are late but that has nothing to do with crash’s timer cmd.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory (crash bug fix and enhancement update), and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://access.redhat.com/errata/RHBA-2022:1864
Description of problem: In RHEL 8 the hrtimer_cpu_base struct now contains 8 hrtimer_clock_base ‘s and crash timer cmd does not account for them. It needs to be updated. Crash version: Crash 7.3.1++ GNU gdb (GDB) 7.6 crash> hrtimer_cpu_base struct hrtimer_cpu_base { raw_spinlock_t lock; unsigned int cpu; unsigned int active_bases; unsigned int clock_was_set_seq; unsigned int hres_active : 1; unsigned int in_hrtirq : 1; unsigned int hang_detected : 1; unsigned int softirq_activated : 1; unsigned int nr_events; unsigned short nr_retries; unsigned short nr_hangs; unsigned int max_hang_time; spinlock_t softirq_expiry_lock; atomic_t timer_waiters; ktime_t expires_next; struct hrtimer *next_timer; ktime_t softirq_expires_next; struct hrtimer *softirq_next_timer; struct hrtimer_clock_base clock_base[8]; <---- } SIZE: 0x480 crash> Version-Release number of selected component (if applicable): Crash version: Crash 7.3.1++ GNU gdb (GDB) 7.6 How reproducible: always. Steps to Reproduce: 1.run crash on a rhel8 dump. 2. 3. Actual results: Expected results: Additional info: Example from dump: Dump files: KERNEL: /cores/retrace/repos/kernel/x86_64/usr/lib/debug/lib/modules/4.18.0-305.19.1.rt7.91.el8_4.x86_64/vmlinux [TAINTED] DUMPFILE: /cores/retrace/tasks/510256984/crash/vmcore [PARTIAL DUMP] Timer cmd: crash> timer -r -C 11 CPU: 11 HRTIMER_CPU_BASE: ffff8f829f95ee00 CLOCK: 0 HRTIMER_CLOCK_BASE: ffff8f829f95ee80 [ktime_get] (empty) CLOCK: 1 HRTIMER_CLOCK_BASE: ffff8f829f95ef00 [ktime_get_real] (empty) CLOCK: 2 HRTIMER_CLOCK_BASE: ffff8f829f95ef80 [ktime_get_boottime] (empty) crash> In this dump we are actually waiting for a timer on CPU 11 clock 4 to be run. I hard coded the clocks to show all 8 of them. Same dump: crash-vl> sys KERNEL: /cores/retrace/repos/kernel/x86_64/usr/lib/debug/lib/modules/4.18.0-305.19.1.rt7.91.el8_4.x86_64/vmlinux DUMPFILE: /cores/retrace/tasks/510256984/crash/vmcore [PARTIAL DUMP] Now you can see the timers we are waiting on clock 4 and 5. crash-vl> timer -r -C 11 CPU: 11 HRTIMER_CPU_BASE: ffff9a775f95ee00 CLOCK: 0 HRTIMER_CLOCK_BASE: ffff9a775f95ee80 [ktime_get] (empty) CLOCK: 1 HRTIMER_CLOCK_BASE: ffff9a775f95ef00 [ktime_get_real] (empty) CLOCK: 2 HRTIMER_CLOCK_BASE: ffff9a775f95ef80 [ktime_get_boottime] (empty) CLOCK: 3 HRTIMER_CLOCK_BASE: ffff9a775f95f000 [ktime_get_clocktai] (empty) CLOCK: 4 HRTIMER_CLOCK_BASE: ffff9a775f95f080 [ktime_get] CURRENT 48114047000000 SOFTEXPIRES EXPIRES TTE HRTIMER FUNCTION 48048203002814 48048203052814 -65843947186 ffffae5889f67e78 ffffffff96770fa0 <hrtimer_wakeup> CLOCK: 5 HRTIMER_CLOCK_BASE: ffff9a775f95f100 [ktime_get_real] CURRENT 1640021151290259551 SOFTEXPIRES EXPIRES TTE HRTIMER FUNCTION 1640021064148260307 1640021064148310307 -87141949244 ffffae588a9c7d30 ffffffff96770fa0 <hrtimer_wakeup> CLOCK: 6 HRTIMER_CLOCK_BASE: ffff9a775f95f180 [ktime_get_boottime] (empty) CLOCK: 7 HRTIMER_CLOCK_BASE: ffff9a775f95f200 [ktime_get_clocktai] (empty) crash-vl> The real issue in the dump is that they are late but that has nothing to do with crash’s timer cmd.