Affected: Linux, Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem, Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

In the Linux kernel, the following vulnerability has been resolved:

x86: stop playing stack games in profile_pc()

The 'profile_pc()' function is used for timer-based profiling, which isn't really all that relevant any more to begin with, but it also ends up making assumptions based on the stack layout that aren't necessarily valid.

Basically, the code tries to account the time spent in spinlocks to the caller rather than the spinlock, and while I support that as a concept, it's not worth the code complexity or the KASAN warnings when no serious profiling is done using timers anyway these days.

And the code really does depend on stack layout that is only true in the simplest of cases. We've lost the comment at some point (I think when the 32-bit and 64-bit code was unified), but it used to say:

Assume the lock function has either no stack frame or a copy of eflags from PUSHF.

which explains why it just blindly loads a word or two straight off the stack pointer and then takes a minimal look at the values to just check if they might be eflags or the return pc:

Eflags always has bits 22 and up cleared unlike kernel addresses

but that basic stack layout assumption assumes that there isn't any lock debugging etc going on that would complicate the code and cause a stack frame.

It causes KASAN unhappiness reported for years by syzkaller [1] and others [2].

With no real practical reason for this any more, just remove the code.

Just for historical interest, here's some…

Affected: Ubuntu:20.04:LTS: linux, Ubuntu:20.04:LTS: linux-aws, Ubuntu:20.04:LTS: linux-azure, Ubuntu:20.04:LTS: linux-bluefield, Ubuntu:20.04:LTS: linux-gcp, Ubuntu:20.04:LTS: linux-gkeop, Ubuntu:20.04:LTS: linux-ibm, Ubuntu:20.04:LTS: linux-kvm, Ubuntu:20.04:LTS: linux-oracle

It was discovered that the JFS file system contained an out-of-bounds read vulnerability when printing xattr debug information. A local attacker could use this to cause a denial of service (system crash). (CVE-2024-40902)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - MIPS architecture; - PowerPC architecture; - x86 architecture; - ACPI drivers; - Serial ATA and Parallel ATA drivers; - Drivers core; - GPIO subsystem; - GPU drivers; - Greybus drivers; - HID subsystem; - I2C subsystem; - IIO subsystem; - InfiniBand drivers; - Media drivers; - VMware VMCI Driver; - Network drivers; - Pin controllers subsystem; - S/390 drivers; - SCSI drivers; - USB subsystem; - JFFS2 file system; - JFS file system; - File systems infrastructure; - NILFS2 file system; - IOMMU subsystem; - Sun RPC protocol; - Netfilter; - Memory management; - B.A.T.M.A.N. meshing protocol; - CAN network layer; - Ceph Core library; - Networking core; - IPv4 networking; - IPv6 networking; - IUCV driver; - MAC80211 subsystem; - NET/ROM layer; - Network traffic control; - SoC Audio for Freescale CPUs drivers; (CVE-2024-40905, CVE-2024-41095, CVE-2024-41035, CVE-2024-36974, CVE-2024-40959, CVE-2024-40978, CVE-2024-42236, CVE-2024-40963, CVE-2024-40916, CVE-2024-41006, CVE-2024-39495, CVE-2023-52803, CVE-2024…