{"id":"DEBIAN-CVE-2022-48983","details":"In the Linux kernel, the following vulnerability has been resolved:  io_uring: Fix a null-ptr-deref in io_tctx_exit_cb()  Syzkaller reports a NULL deref bug as follows:   BUG: KASAN: null-ptr-deref in io_tctx_exit_cb+0x53/0xd3  Read of size 4 at addr 0000000000000138 by task file1/1955   CPU: 1 PID: 1955 Comm: file1 Not tainted 6.1.0-rc7-00103-gef4d3ea40565 #75  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014  Call Trace:   \u003cTASK\u003e   dump_stack_lvl+0xcd/0x134   ? io_tctx_exit_cb+0x53/0xd3   kasan_report+0xbb/0x1f0   ? io_tctx_exit_cb+0x53/0xd3   kasan_check_range+0x140/0x190   io_tctx_exit_cb+0x53/0xd3   task_work_run+0x164/0x250   ? task_work_cancel+0x30/0x30   get_signal+0x1c3/0x2440   ? lock_downgrade+0x6e0/0x6e0   ? lock_downgrade+0x6e0/0x6e0   ? exit_signals+0x8b0/0x8b0   ? do_raw_read_unlock+0x3b/0x70   ? do_raw_spin_unlock+0x50/0x230   arch_do_signal_or_restart+0x82/0x2470   ? kmem_cache_free+0x260/0x4b0   ? putname+0xfe/0x140   ? get_sigframe_size+0x10/0x10   ? do_execveat_common.isra.0+0x226/0x710   ? lockdep_hardirqs_on+0x79/0x100   ? putname+0xfe/0x140   ? do_execveat_common.isra.0+0x238/0x710   exit_to_user_mode_prepare+0x15f/0x250   syscall_exit_to_user_mode+0x19/0x50   do_syscall_64+0x42/0xb0   entry_SYSCALL_64_after_hwframe+0x63/0xcd  RIP: 0023:0x0  Code: Unable to access opcode bytes at 0xffffffffffffffd6.  RSP: 002b:00000000fffb7790 EFLAGS: 00000200 ORIG_RAX: 000000000000000b  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000  RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000  R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000  R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000   \u003c/TASK\u003e  Kernel panic - not syncing: panic_on_warn set ...  This happens because the adding of task_work from io_ring_exit_work() isn't synchronized with canceling all work items from eg exec. The execution of the two are ordered in that they are both run by the task itself, but if io_tctx_exit_cb() is queued while we're canceling all work items off exec AND gets executed when the task exits to userspace rather than in the main loop in io_uring_cancel_generic(), then we can find current-\u003eio_uring == NULL and hit the above crash.  It's safe to add this NULL check here, because the execution of the two paths are done by the task itself.  [axboe: add code comment and also put an explanation in the commit msg]","modified":"2026-08-27T23:04:45.957363418Z","published":"2024-10-21T20:15:10.283Z","upstream":["CVE-2022-48983"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2022-48983"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.4-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-48983.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.4-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-48983.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.4-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2022-48983.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}