{"id":"AZL-50882","summary":"CVE-2024-47691 affecting package kernel for versions less than 6.6.56.1-5","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nf2fs: fix to avoid use-after-free in f2fs_stop_gc_thread()\n\nsyzbot reports a f2fs bug as below:\n\n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114\n print_report+0xe8/0x550 mm/kasan/report.c:491\n kasan_report+0x143/0x180 mm/kasan/report.c:601\n kasan_check_range+0x282/0x290 mm/kasan/generic.c:189\n instrument_atomic_read_write include/linux/instrumented.h:96 [inline]\n atomic_fetch_add_relaxed include/linux/atomic/atomic-instrumented.h:252 [inline]\n __refcount_add include/linux/refcount.h:184 [inline]\n __refcount_inc include/linux/refcount.h:241 [inline]\n refcount_inc include/linux/refcount.h:258 [inline]\n get_task_struct include/linux/sched/task.h:118 [inline]\n kthread_stop+0xca/0x630 kernel/kthread.c:704\n f2fs_stop_gc_thread+0x65/0xb0 fs/f2fs/gc.c:210\n f2fs_do_shutdown+0x192/0x540 fs/f2fs/file.c:2283\n f2fs_ioc_shutdown fs/f2fs/file.c:2325 [inline]\n __f2fs_ioctl+0x443a/0xbe60 fs/f2fs/file.c:4325\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:907 [inline]\n __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nThe root cause is below race condition, it may cause use-after-free\nissue in sbi-\u003egc_th pointer.\n\n- remount\n - f2fs_remount\n  - f2fs_stop_gc_thread\n   - kfree(gc_th)\n\t\t\t\t- f2fs_ioc_shutdown\n\t\t\t\t - f2fs_do_shutdown\n\t\t\t\t  - f2fs_stop_gc_thread\n\t\t\t\t   - kthread_stop(gc_th-\u003ef2fs_gc_task)\n   : sbi-\u003egc_thread = NULL;\n\nWe will call f2fs_do_shutdown() in two paths:\n- for f2fs_ioc_shutdown() path, we should grab sb-\u003es_umount semaphore\nfor fixing.\n- for f2fs_shutdown() path, it's safe since caller has already grabbed\nsb-\u003es_umount semaphore.","modified":"2026-04-01T05:16:20.816463Z","published":"2024-10-21T12:15:05Z","upstream":["CVE-2024-47691"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-47691"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.56.1-5"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-50882.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}