| Message ID | 20221118121143.267895-2-guoxuenan@huawei.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [v5,1/2] xfs: wait iclog complete before tearing down AIL | expand |
On Fri, Nov 18, 2022 at 08:11:42PM +0800, Guo Xuenan wrote: > Fix uaf in xfs_trans_ail_delete during xlog force shutdown. > In commit cd6f79d1fb32 ("xfs: run callbacks before waking waiters in > xlog_state_shutdown_callbacks") changed the order of running callbacks > and wait for iclog completion to avoid unmount path untimely destroy AIL. > But which seems not enough to ensue this, adding mdelay in > `xfs_buf_item_unpin` can prove that. > > The reproduction is as follows. To ensure destroy AIL safely, > we should wait all xlog ioend workers done and sync the AIL. > > ================================================================== > BUG: KASAN: use-after-free in xfs_trans_ail_delete+0x240/0x2a0 > Read of size 8 at addr ffff888023169400 by task kworker/1:1H/43 > > CPU: 1 PID: 43 Comm: kworker/1:1H Tainted: G W > 6.1.0-rc1-00002-gc28266863c4a #137 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > 1.13.0-1ubuntu1.1 04/01/2014 > Workqueue: xfs-log/sda xlog_ioend_work > Call Trace: > <TASK> > dump_stack_lvl+0x4d/0x66 > print_report+0x171/0x4a6 > kasan_report+0xb3/0x130 > xfs_trans_ail_delete+0x240/0x2a0 > xfs_buf_item_done+0x7b/0xa0 > xfs_buf_ioend+0x1e9/0x11f0 > xfs_buf_item_unpin+0x4c8/0x860 > xfs_trans_committed_bulk+0x4c2/0x7c0 > xlog_cil_committed+0xab6/0xfb0 > xlog_cil_process_committed+0x117/0x1e0 > xlog_state_shutdown_callbacks+0x208/0x440 > xlog_force_shutdown+0x1b3/0x3a0 > xlog_ioend_work+0xef/0x1d0 > process_one_work+0x6f9/0xf70 > worker_thread+0x578/0xf30 > kthread+0x28c/0x330 > ret_from_fork+0x1f/0x30 > </TASK> > > Allocated by task 9606: > kasan_save_stack+0x1e/0x40 > kasan_set_track+0x21/0x30 > __kasan_kmalloc+0x7a/0x90 > __kmalloc+0x59/0x140 > kmem_alloc+0xb2/0x2f0 > xfs_trans_ail_init+0x20/0x320 > xfs_log_mount+0x37e/0x690 > xfs_mountfs+0xe36/0x1b40 > xfs_fs_fill_super+0xc5c/0x1a70 > get_tree_bdev+0x3c5/0x6c0 > vfs_get_tree+0x85/0x250 > path_mount+0xec3/0x1830 > do_mount+0xef/0x110 > __x64_sys_mount+0x150/0x1f0 > do_syscall_64+0x35/0x80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > Freed by task 9662: > kasan_save_stack+0x1e/0x40 > kasan_set_track+0x21/0x30 > kasan_save_free_info+0x2a/0x40 > __kasan_slab_free+0x105/0x1a0 > __kmem_cache_free+0x99/0x2d0 > kvfree+0x3a/0x40 > xfs_log_unmount+0x60/0xf0 > xfs_unmountfs+0xf3/0x1d0 > xfs_fs_put_super+0x78/0x300 > generic_shutdown_super+0x151/0x400 > kill_block_super+0x9a/0xe0 > deactivate_locked_super+0x82/0xe0 > deactivate_super+0x91/0xb0 > cleanup_mnt+0x32a/0x4a0 > task_work_run+0x15f/0x240 > exit_to_user_mode_prepare+0x188/0x190 > syscall_exit_to_user_mode+0x12/0x30 > do_syscall_64+0x42/0x80 > entry_SYSCALL_64_after_hwframe+0x63/0xcd > > The buggy address belongs to the object at ffff888023169400 > which belongs to the cache kmalloc-128 of size 128 > The buggy address is located 0 bytes inside of > 128-byte region [ffff888023169400, ffff888023169480) > > The buggy address belongs to the physical page: > page:ffffea00008c5a00 refcount:1 mapcount:0 mapping:0000000000000000 > index:0xffff888023168f80 pfn:0x23168 > head:ffffea00008c5a00 order:1 compound_mapcount:0 compound_pincount:0 > flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) > raw: 001fffff80010200 ffffea00006b3988 ffffea0000577a88 ffff88800f842ac0 > raw: ffff888023168f80 0000000000150007 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff888023169300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff888023169380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > >ffff888023169400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff888023169480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ffff888023169500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > ================================================================== > Disabling lock debugging due to kernel taint > > Fixes: cd6f79d1fb32 ("xfs: run callbacks before waking waiters in xlog_state_shutdown_callbacks") > Signed-off-by: Guo Xuenan <guoxuenan@huawei.com> > --- > fs/xfs/xfs_log.c | 36 +++++++++++++++++++++++++----------- > 1 file changed, 25 insertions(+), 11 deletions(-) > > diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c > index 0141d9907d31..fc61cc024023 100644 > --- a/fs/xfs/xfs_log.c > +++ b/fs/xfs/xfs_log.c > @@ -888,6 +888,23 @@ xlog_force_iclog( > return xlog_state_release_iclog(iclog->ic_log, iclog, NULL); > } > > +/* > + * Cycle all the iclogbuf locks to make sure all log IO completion > + * is done before we tear down these buffers. > + */ > +static void > +xlog_wait_iclog_completion(struct xlog *log) > +{ > + int i; > + struct xlog_in_core *iclog = log->l_iclog; > + > + for (i = 0; i < log->l_iclog_bufs; i++) { > + down(&iclog->ic_sema); > + up(&iclog->ic_sema); > + iclog = iclog->ic_next; > + } > +} > + > /* > * Wait for the iclog and all prior iclogs to be written disk as required by the > * log force state machine. Waiting on ic_force_wait ensures iclog completions > @@ -1113,6 +1130,14 @@ xfs_log_unmount( > { > xfs_log_clean(mp); > > + /* > + * If shutdown has come from iclog IO context, the log > + * cleaning will have been skipped and so we need to wait > + * for the iclog to complete shutdown processing before we > + * tear anything down. > + */ > + xlog_wait_iclog_completion(mp->m_log); > + > xfs_buftarg_drain(mp->m_ddev_targp); > > xfs_trans_ail_destroy(mp); > @@ -2115,17 +2140,6 @@ xlog_dealloc_log( > xlog_in_core_t *iclog, *next_iclog; > int i; > > - /* > - * Cycle all the iclogbuf locks to make sure all log IO completion > - * is done before we tear down these buffers. > - */ > - iclog = log->l_iclog; > - for (i = 0; i < log->l_iclog_bufs; i++) { > - down(&iclog->ic_sema); > - up(&iclog->ic_sema); > - iclog = iclog->ic_next; > - } Why is it ok to remove this loop here? If the xlog_recover() call in xfs_log_mount shuts down the log, don't we still need to cycle the iclog locks to make sure the completions have all run before we free them? --D > - > /* > * Destroy the CIL after waiting for iclog IO completion because an > * iclog EIO error will try to shut down the log, which accesses the > -- > 2.31.1 >
On 2022/11/22 2:11, Darrick J. Wong wrote: > On Fri, Nov 18, 2022 at 08:11:42PM +0800, Guo Xuenan wrote: >> Fix uaf in xfs_trans_ail_delete during xlog force shutdown. >> In commit cd6f79d1fb32 ("xfs: run callbacks before waking waiters in >> xlog_state_shutdown_callbacks") changed the order of running callbacks >> and wait for iclog completion to avoid unmount path untimely destroy AIL. >> But which seems not enough to ensue this, adding mdelay in >> `xfs_buf_item_unpin` can prove that. >> >> The reproduction is as follows. To ensure destroy AIL safely, >> we should wait all xlog ioend workers done and sync the AIL. >> >> ================================================================== >> BUG: KASAN: use-after-free in xfs_trans_ail_delete+0x240/0x2a0 >> Read of size 8 at addr ffff888023169400 by task kworker/1:1H/43 >> >> CPU: 1 PID: 43 Comm: kworker/1:1H Tainted: G W >> 6.1.0-rc1-00002-gc28266863c4a #137 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS >> 1.13.0-1ubuntu1.1 04/01/2014 >> Workqueue: xfs-log/sda xlog_ioend_work >> Call Trace: >> <TASK> >> dump_stack_lvl+0x4d/0x66 >> print_report+0x171/0x4a6 >> kasan_report+0xb3/0x130 >> xfs_trans_ail_delete+0x240/0x2a0 >> xfs_buf_item_done+0x7b/0xa0 >> xfs_buf_ioend+0x1e9/0x11f0 >> xfs_buf_item_unpin+0x4c8/0x860 >> xfs_trans_committed_bulk+0x4c2/0x7c0 >> xlog_cil_committed+0xab6/0xfb0 >> xlog_cil_process_committed+0x117/0x1e0 >> xlog_state_shutdown_callbacks+0x208/0x440 >> xlog_force_shutdown+0x1b3/0x3a0 >> xlog_ioend_work+0xef/0x1d0 >> process_one_work+0x6f9/0xf70 >> worker_thread+0x578/0xf30 >> kthread+0x28c/0x330 >> ret_from_fork+0x1f/0x30 >> </TASK> >> >> Allocated by task 9606: >> kasan_save_stack+0x1e/0x40 >> kasan_set_track+0x21/0x30 >> __kasan_kmalloc+0x7a/0x90 >> __kmalloc+0x59/0x140 >> kmem_alloc+0xb2/0x2f0 >> xfs_trans_ail_init+0x20/0x320 >> xfs_log_mount+0x37e/0x690 >> xfs_mountfs+0xe36/0x1b40 >> xfs_fs_fill_super+0xc5c/0x1a70 >> get_tree_bdev+0x3c5/0x6c0 >> vfs_get_tree+0x85/0x250 >> path_mount+0xec3/0x1830 >> do_mount+0xef/0x110 >> __x64_sys_mount+0x150/0x1f0 >> do_syscall_64+0x35/0x80 >> entry_SYSCALL_64_after_hwframe+0x63/0xcd >> >> Freed by task 9662: >> kasan_save_stack+0x1e/0x40 >> kasan_set_track+0x21/0x30 >> kasan_save_free_info+0x2a/0x40 >> __kasan_slab_free+0x105/0x1a0 >> __kmem_cache_free+0x99/0x2d0 >> kvfree+0x3a/0x40 >> xfs_log_unmount+0x60/0xf0 >> xfs_unmountfs+0xf3/0x1d0 >> xfs_fs_put_super+0x78/0x300 >> generic_shutdown_super+0x151/0x400 >> kill_block_super+0x9a/0xe0 >> deactivate_locked_super+0x82/0xe0 >> deactivate_super+0x91/0xb0 >> cleanup_mnt+0x32a/0x4a0 >> task_work_run+0x15f/0x240 >> exit_to_user_mode_prepare+0x188/0x190 >> syscall_exit_to_user_mode+0x12/0x30 >> do_syscall_64+0x42/0x80 >> entry_SYSCALL_64_after_hwframe+0x63/0xcd >> >> The buggy address belongs to the object at ffff888023169400 >> which belongs to the cache kmalloc-128 of size 128 >> The buggy address is located 0 bytes inside of >> 128-byte region [ffff888023169400, ffff888023169480) >> >> The buggy address belongs to the physical page: >> page:ffffea00008c5a00 refcount:1 mapcount:0 mapping:0000000000000000 >> index:0xffff888023168f80 pfn:0x23168 >> head:ffffea00008c5a00 order:1 compound_mapcount:0 compound_pincount:0 >> flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) >> raw: 001fffff80010200 ffffea00006b3988 ffffea0000577a88 ffff88800f842ac0 >> raw: ffff888023168f80 0000000000150007 00000001ffffffff 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ffff888023169300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff888023169380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >>> ffff888023169400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ^ >> ffff888023169480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ffff888023169500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >> ================================================================== >> Disabling lock debugging due to kernel taint >> >> Fixes: cd6f79d1fb32 ("xfs: run callbacks before waking waiters in xlog_state_shutdown_callbacks") >> Signed-off-by: Guo Xuenan <guoxuenan@huawei.com> >> --- >> fs/xfs/xfs_log.c | 36 +++++++++++++++++++++++++----------- >> 1 file changed, 25 insertions(+), 11 deletions(-) >> >> diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c >> index 0141d9907d31..fc61cc024023 100644 >> --- a/fs/xfs/xfs_log.c >> +++ b/fs/xfs/xfs_log.c >> @@ -888,6 +888,23 @@ xlog_force_iclog( >> return xlog_state_release_iclog(iclog->ic_log, iclog, NULL); >> } >> >> +/* >> + * Cycle all the iclogbuf locks to make sure all log IO completion >> + * is done before we tear down these buffers. >> + */ >> +static void >> +xlog_wait_iclog_completion(struct xlog *log) >> +{ >> + int i; >> + struct xlog_in_core *iclog = log->l_iclog; >> + >> + for (i = 0; i < log->l_iclog_bufs; i++) { >> + down(&iclog->ic_sema); >> + up(&iclog->ic_sema); >> + iclog = iclog->ic_next; >> + } >> +} >> + >> /* >> * Wait for the iclog and all prior iclogs to be written disk as required by the >> * log force state machine. Waiting on ic_force_wait ensures iclog completions >> @@ -1113,6 +1130,14 @@ xfs_log_unmount( >> { >> xfs_log_clean(mp); >> >> + /* >> + * If shutdown has come from iclog IO context, the log >> + * cleaning will have been skipped and so we need to wait >> + * for the iclog to complete shutdown processing before we >> + * tear anything down. >> + */ >> + xlog_wait_iclog_completion(mp->m_log); >> + >> xfs_buftarg_drain(mp->m_ddev_targp); >> >> xfs_trans_ail_destroy(mp); >> @@ -2115,17 +2140,6 @@ xlog_dealloc_log( >> xlog_in_core_t *iclog, *next_iclog; >> int i; >> >> - /* >> - * Cycle all the iclogbuf locks to make sure all log IO completion >> - * is done before we tear down these buffers. >> - */ >> - iclog = log->l_iclog; >> - for (i = 0; i < log->l_iclog_bufs; i++) { >> - down(&iclog->ic_sema); >> - up(&iclog->ic_sema); >> - iclog = iclog->ic_next; >> - } > Why is it ok to remove this loop here? If the xlog_recover() call in > xfs_log_mount shuts down the log, don't we still need to cycle the iclog > locks to make sure the completions have all run before we free them? Dave provided some opinions here [1]. > "And the iclog walk can be removed from xlog_dealloc_log() as we've already done the checks it needs before tearing down the iclogs...." [1]https://lore.kernel.org/all/20221116060229.GC3600936@dread.disaster.area/ > --D > >> - >> /* >> * Destroy the CIL after waiting for iclog IO completion because an >> * iclog EIO error will try to shut down the log, which accesses the >> -- >> 2.31.1 >> > .
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 0141d9907d31..fc61cc024023 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -888,6 +888,23 @@ xlog_force_iclog( return xlog_state_release_iclog(iclog->ic_log, iclog, NULL); } +/* + * Cycle all the iclogbuf locks to make sure all log IO completion + * is done before we tear down these buffers. + */ +static void +xlog_wait_iclog_completion(struct xlog *log) +{ + int i; + struct xlog_in_core *iclog = log->l_iclog; + + for (i = 0; i < log->l_iclog_bufs; i++) { + down(&iclog->ic_sema); + up(&iclog->ic_sema); + iclog = iclog->ic_next; + } +} + /* * Wait for the iclog and all prior iclogs to be written disk as required by the * log force state machine. Waiting on ic_force_wait ensures iclog completions @@ -1113,6 +1130,14 @@ xfs_log_unmount( { xfs_log_clean(mp); + /* + * If shutdown has come from iclog IO context, the log + * cleaning will have been skipped and so we need to wait + * for the iclog to complete shutdown processing before we + * tear anything down. + */ + xlog_wait_iclog_completion(mp->m_log); + xfs_buftarg_drain(mp->m_ddev_targp); xfs_trans_ail_destroy(mp); @@ -2115,17 +2140,6 @@ xlog_dealloc_log( xlog_in_core_t *iclog, *next_iclog; int i; - /* - * Cycle all the iclogbuf locks to make sure all log IO completion - * is done before we tear down these buffers. - */ - iclog = log->l_iclog; - for (i = 0; i < log->l_iclog_bufs; i++) { - down(&iclog->ic_sema); - up(&iclog->ic_sema); - iclog = iclog->ic_next; - } - /* * Destroy the CIL after waiting for iclog IO completion because an * iclog EIO error will try to shut down the log, which accesses the
Fix uaf in xfs_trans_ail_delete during xlog force shutdown. In commit cd6f79d1fb32 ("xfs: run callbacks before waking waiters in xlog_state_shutdown_callbacks") changed the order of running callbacks and wait for iclog completion to avoid unmount path untimely destroy AIL. But which seems not enough to ensue this, adding mdelay in `xfs_buf_item_unpin` can prove that. The reproduction is as follows. To ensure destroy AIL safely, we should wait all xlog ioend workers done and sync the AIL. ================================================================== BUG: KASAN: use-after-free in xfs_trans_ail_delete+0x240/0x2a0 Read of size 8 at addr ffff888023169400 by task kworker/1:1H/43 CPU: 1 PID: 43 Comm: kworker/1:1H Tainted: G W 6.1.0-rc1-00002-gc28266863c4a #137 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Workqueue: xfs-log/sda xlog_ioend_work Call Trace: <TASK> dump_stack_lvl+0x4d/0x66 print_report+0x171/0x4a6 kasan_report+0xb3/0x130 xfs_trans_ail_delete+0x240/0x2a0 xfs_buf_item_done+0x7b/0xa0 xfs_buf_ioend+0x1e9/0x11f0 xfs_buf_item_unpin+0x4c8/0x860 xfs_trans_committed_bulk+0x4c2/0x7c0 xlog_cil_committed+0xab6/0xfb0 xlog_cil_process_committed+0x117/0x1e0 xlog_state_shutdown_callbacks+0x208/0x440 xlog_force_shutdown+0x1b3/0x3a0 xlog_ioend_work+0xef/0x1d0 process_one_work+0x6f9/0xf70 worker_thread+0x578/0xf30 kthread+0x28c/0x330 ret_from_fork+0x1f/0x30 </TASK> Allocated by task 9606: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 __kasan_kmalloc+0x7a/0x90 __kmalloc+0x59/0x140 kmem_alloc+0xb2/0x2f0 xfs_trans_ail_init+0x20/0x320 xfs_log_mount+0x37e/0x690 xfs_mountfs+0xe36/0x1b40 xfs_fs_fill_super+0xc5c/0x1a70 get_tree_bdev+0x3c5/0x6c0 vfs_get_tree+0x85/0x250 path_mount+0xec3/0x1830 do_mount+0xef/0x110 __x64_sys_mount+0x150/0x1f0 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 9662: kasan_save_stack+0x1e/0x40 kasan_set_track+0x21/0x30 kasan_save_free_info+0x2a/0x40 __kasan_slab_free+0x105/0x1a0 __kmem_cache_free+0x99/0x2d0 kvfree+0x3a/0x40 xfs_log_unmount+0x60/0xf0 xfs_unmountfs+0xf3/0x1d0 xfs_fs_put_super+0x78/0x300 generic_shutdown_super+0x151/0x400 kill_block_super+0x9a/0xe0 deactivate_locked_super+0x82/0xe0 deactivate_super+0x91/0xb0 cleanup_mnt+0x32a/0x4a0 task_work_run+0x15f/0x240 exit_to_user_mode_prepare+0x188/0x190 syscall_exit_to_user_mode+0x12/0x30 do_syscall_64+0x42/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888023169400 which belongs to the cache kmalloc-128 of size 128 The buggy address is located 0 bytes inside of 128-byte region [ffff888023169400, ffff888023169480) The buggy address belongs to the physical page: page:ffffea00008c5a00 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888023168f80 pfn:0x23168 head:ffffea00008c5a00 order:1 compound_mapcount:0 compound_pincount:0 flags: 0x1fffff80010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) raw: 001fffff80010200 ffffea00006b3988 ffffea0000577a88 ffff88800f842ac0 raw: ffff888023168f80 0000000000150007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888023169300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888023169380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888023169400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888023169480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888023169500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== Disabling lock debugging due to kernel taint Fixes: cd6f79d1fb32 ("xfs: run callbacks before waking waiters in xlog_state_shutdown_callbacks") Signed-off-by: Guo Xuenan <guoxuenan@huawei.com> --- fs/xfs/xfs_log.c | 36 +++++++++++++++++++++++++----------- 1 file changed, 25 insertions(+), 11 deletions(-)