{"id":"AZL-67449","summary":"CVE-2024-40915 affecting package kernel 5.15.200.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: rewrite __kernel_map_pages() to fix sleeping in invalid context\n\n__kernel_map_pages() is a debug function which clears the valid bit in page\ntable entry for deallocated pages to detect illegal memory accesses to\nfreed pages.\n\nThis function set/clear the valid bit using __set_memory(). __set_memory()\nacquires init_mm's semaphore, and this operation may sleep. This is\nproblematic, because  __kernel_map_pages() can be called in atomic context,\nand thus is illegal to sleep. An example warning that this causes:\n\nBUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1578\nin_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 2, name: kthreadd\npreempt_count: 2, expected: 0\nCPU: 0 PID: 2 Comm: kthreadd Not tainted 6.9.0-g1d4c6d784ef6 #37\nHardware name: riscv-virtio,qemu (DT)\nCall Trace:\n[\u003cffffffff800060dc\u003e] dump_backtrace+0x1c/0x24\n[\u003cffffffff8091ef6e\u003e] show_stack+0x2c/0x38\n[\u003cffffffff8092baf8\u003e] dump_stack_lvl+0x5a/0x72\n[\u003cffffffff8092bb24\u003e] dump_stack+0x14/0x1c\n[\u003cffffffff8003b7ac\u003e] __might_resched+0x104/0x10e\n[\u003cffffffff8003b7f4\u003e] __might_sleep+0x3e/0x62\n[\u003cffffffff8093276a\u003e] down_write+0x20/0x72\n[\u003cffffffff8000cf00\u003e] __set_memory+0x82/0x2fa\n[\u003cffffffff8000d324\u003e] __kernel_map_pages+0x5a/0xd4\n[\u003cffffffff80196cca\u003e] __alloc_pages_bulk+0x3b2/0x43a\n[\u003cffffffff8018ee82\u003e] __vmalloc_node_range+0x196/0x6ba\n[\u003cffffffff80011904\u003e] copy_process+0x72c/0x17ec\n[\u003cffffffff80012ab4\u003e] kernel_clone+0x60/0x2fe\n[\u003cffffffff80012f62\u003e] kernel_thread+0x82/0xa0\n[\u003cffffffff8003552c\u003e] kthreadd+0x14a/0x1be\n[\u003cffffffff809357de\u003e] ret_from_fork+0xe/0x1c\n\nRewrite this function with apply_to_existing_page_range(). It is fine to\nnot have any locking, because __kernel_map_pages() works with pages being\nallocated/deallocated and those pages are not changed by anyone else in the\nmeantime.","modified":"2026-04-01T05:21:12.629131Z","published":"2024-07-12T13:15:14Z","upstream":["CVE-2024-40915"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-40915"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:2","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.15.200.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-67449.json"}}],"schema_version":"1.7.5"}