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Diffstat (limited to 'results/classifier/gemma3:12b/kernel/650')
| -rw-r--r-- | results/classifier/gemma3:12b/kernel/650 | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/results/classifier/gemma3:12b/kernel/650 b/results/classifier/gemma3:12b/kernel/650 new file mode 100644 index 00000000..2abb430e --- /dev/null +++ b/results/classifier/gemma3:12b/kernel/650 @@ -0,0 +1,25 @@ + +Monitor device_add triggers deadlock when calling drain_call_rcu on QEMU >= 6.0.0 +Description of problem: +It hangs +Steps to reproduce: +1. Run the QEMU: + ``` + ./qemu-system-mips64 -nographic + ``` +2. Enter into the QEMU monitor: press ctrl-a c +3. Execute command `device_add` without arguments: +``` +(qemu) device_add +``` +4. It hangs so bad that only `kill -9` helps +Additional information: +I didn't test versions between 4.2.0 and 6.0.0, but I can confirm that 6.0.0, 6.1.0 and the latest master pull have this bug, while version 4.2.0 doesn't have it. + +I've tracked the problem and found this. + +1. Command `device_add` calls function `drain_call_rcu`. `drain_call_rcu` waits indefinitely for drain_complete_event. +2. Function `cpu_exec` in accel/tcg/cpu-exec.c calls `rcu_read_lock` but does not call `rcu_read_unlock()`. `cpu_exec` just spins in its inner loop. +3. Function `call_rcu_thread` hanged in calling the `synchronize_rcu` which calls `wait_for_readers`. + +If I execute `stop` command in QEMU monitor before calling `device_add` command, no hang happen. |