kernel: block, bfq: Fix division by zero error on zero wsum

A division by zero error was found in the BFQ I/O scheduler. When the weighted sum of I/O priorities becomes zero, the limit calculation divides by zero, causing a kernel crash...

An issue was discovered in the Linux kernel before 5.6.5. There is a use-after-free in block/bfq-iosched.c related to bfq_idle_slice_timer_body.

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kernel: use-after-free in block/bfq-iosched.c related to bfq_idle_slice_timer_body

A flaw was found in the Linux kernel's implementation of the BFQ IO scheduler. This flaw allows a local user able to groom system memory to cause kernel memory corruption and possible privilege escalation by abusing a race condition in the IO scheduler...

The vulnerability of the `bfq_idle_slice_timer_body` function in the Linux kernel allows a attacker to compromise the confidentiality, integrity, and accessibility of the protected information.

The vulnerability of the bfqidleslicetimerbody function in the Linux kernel’s block/bfq-iosched.c file relates to the use of memory after it is freed. Exploiting this vulnerability could allow an attacker to compromise the confidentiality, integrity, and accessibility of the protected information...

CVE-2020-12657

A flaw was found in the Linux kernel's implementation of the BFQ IO scheduler. This flaw allows a local user able to groom system memory to cause kernel memory corruption and possible privilege escalation by abusing a race condition in the IO scheduler. Mitigation The default io scheduler for Red...