Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:[EOL][EOL]fs: writeback: fix use-after-free in __mark_inode_dirty()[EOL][EOL]An use-after-free issue occurred when __mark_inode_dirty() get the[EOL]bdi_writeback that was in the progress of switching.[EOL][EOL]CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1[EOL]......[EOL]pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)[EOL]pc : __mark_inode_dirty+0x124/0x418[EOL]lr : __mark_inode_dirty+0x118/0x418[EOL]sp : ffffffc08c9dbbc0[EOL]........[EOL]Call trace:[EOL] __mark_inode_dirty+0x124/0x418[EOL] generic_update_time+0x4c/0x60[EOL] file_modified+0xcc/0xd0[EOL] ext4_buffered_write_iter+0x58/0x124[EOL] ext4_file_write_iter+0x54/0x704[EOL] vfs_write+0x1c0/0x308[EOL] ksys_write+0x74/0x10c[EOL] __arm64_sys_write+0x1c/0x28[EOL] invoke_syscall+0x48/0x114[EOL] el0_svc_common.constprop.0+0xc0/0xe0[EOL] do_el0_svc+0x1c/0x28[EOL] el0_svc+0x40/0xe4[EOL] el0t_64_sync_handler+0x120/0x12c[EOL] el0t_64_sync+0x194/0x198[EOL][EOL]Root cause is:[EOL][EOL]systemd-random-seed                         kworker[EOL]----------------------------------------------------------------------[EOL]___mark_inode_dirty                     inode_switch_wbs_work_fn[EOL][EOL]  spin_lock(&inode->i_lock);[EOL]  inode_attach_wb[EOL]  locked_inode_to_wb_and_lock_list[EOL]     get inode->i_wb[EOL]     spin_unlock(&inode->i_lock);[EOL]     spin_lock(&wb->list_lock)[EOL]  spin_lock(&inode->i_lock)[EOL]  inode_io_list_move_locked[EOL]  spin_unlock(&wb->list_lock)[EOL]  spin_unlock(&inode->i_lock)[EOL]                                    spin_lock(&old_wb->list_lock)[EOL]                                      inode_do_switch_wbs[EOL]                                        spin_lock(&inode->i_lock)[EOL]                                        inode->i_wb = new_wb[EOL]                                        spin_unlock(&inode->i_lock)[EOL]                                    spin_unlock(&old_wb->list_lock)[EOL]                                    wb_put_many(old_wb, nr_switched)[EOL]                                      cgwb_release[EOL]                                      old wb released[EOL]  wb_wakeup_delayed() accesses wb,[EOL]  then trigger the use-after-free[EOL]  issue[EOL][EOL]Fix this race condition by holding inode spinlock until[EOL]wb_wakeup_delayed() finished.