commit 51eba7e6c91ada319dc9ebee3f88e4472b5efbc4 Author: Greg Kroah-Hartman Date: Fri May 15 14:51:08 2026 +0200 Linux 6.12.89 Signed-off-by: Greg Kroah-Hartman commit 6e5b51e74a40d377bcd3081dd33fbaa0e1aa7e3d Author: Linus Torvalds Date: Wed May 13 11:37:18 2026 -0700 ptrace: slightly saner 'get_dumpable()' logic commit 31e62c2ebbfdc3fe3dbdf5e02c92a9dc67087a3a upstream. The 'dumpability' of a task is fundamentally about the memory image of the task - the concept comes from whether it can core dump or not - and makes no sense when you don't have an associated mm. And almost all users do in fact use it only for the case where the task has a mm pointer. But we have one odd special case: ptrace_may_access() uses 'dumpable' to check various other things entirely independently of the MM (typically explicitly using flags like PTRACE_MODE_READ_FSCREDS). Including for threads that no longer have a VM (and maybe never did, like most kernel threads). It's not what this flag was designed for, but it is what it is. The ptrace code does check that the uid/gid matches, so you do have to be uid-0 to see kernel thread details, but this means that the traditional "drop capabilities" model doesn't make any difference for this all. Make it all make a *bit* more sense by saying that if you don't have a MM pointer, we'll use a cached "last dumpability" flag if the thread ever had a MM (it will be zero for kernel threads since it is never set), and require a proper CAP_SYS_PTRACE capability to override. Reported-by: Qualys Security Advisory Cc: Oleg Nesterov Cc: Kees Cook Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman