Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
mm/swapfile: add cond_resched() in get_swap_pages()
The softlockup still occurs in get_swap_pages() under memory pressure. 64 CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram device is 50MB with same priority as si. Use the stress-ng tool to increase memory pressure, causing the system to oom frequently.
The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens of thousands of times to find available space (extreme case: cond_resched() is not called in scan_swap_map_slots()). Let’s add cond_resched() into get_swap_pages() when failed to find available space to avoid softlockup.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CloudLinux 6 ELS , Oracle Linux 6 ELS , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS
- Affected packages:
- linux-hwe @ 4.15.0 (+8 more)
In the Linux kernel, the following vulnerability has been resolved:
mm/swapfile: add cond_resched() in get_swap_pages()
The softlockup still occurs in get_swap_pages() under memory pressure. 64 CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram device is 50MB with same priority as si. Use the stress-ng tool to increase memory pressure, causing the system to oom frequently.
The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens of thousands of times to find available space (extreme case: cond_resched() is not called in scan_swap_map_slots()). Let’s add cond_resched() into get_swap_pages() when failed to find available space to avoid softlockup.