Hello, syzbot found the following issue on:
HEAD commit: a430d95c5efa Merge tag 'lsm-pr-20240911' of git://git.kern.. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=15b24427980000 kernel config: https://syzkaller.appspot.com/x/.config?x=d85e1e571a820894 dashboard link: https://syzkaller.appspot.com/bug?extid=7c48153a9d788824044b compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1511a607980000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10c7d69f980000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/4faaa939b3a4/disk-a430d95c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/83c722076440/vmlinux-a430d95c.xz kernel image: https://storage.googleapis.com/syzbot-assets/24c938d49c40/bzImage-a430d95c.xz The issue was bisected to: commit 983cdcf8fe141b0ce16bc71959a5dc55bcb0764d Author: David Howells <dhowe...@redhat.com> Date: Thu Jun 6 06:48:55 2024 +0000 netfs: Simplify the writeback code bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1087bb00580000 final oops: https://syzkaller.appspot.com/x/report.txt?x=1287bb00580000 console output: https://syzkaller.appspot.com/x/log.txt?x=1487bb00580000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+7c48153a9d7888240...@syzkaller.appspotmail.com Fixes: 983cdcf8fe14 ("netfs: Simplify the writeback code") ================================================================== BUG: KASAN: slab-use-after-free in iov_iter_folioq_advance lib/iov_iter.c:540 [inline] BUG: KASAN: slab-use-after-free in iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 Read of size 8 at addr ffff88802a63dd20 by task syz-executor341/5249 CPU: 1 UID: 0 PID: 5249 Comm: syz-executor341 Not tainted 6.11.0-syzkaller-02574-ga430d95c5efa #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 iov_iter_folioq_advance lib/iov_iter.c:540 [inline] iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 netfs_write_folio+0x745/0x18f0 fs/netfs/write_issue.c:481 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xaa3/0x2bb0 kernel/exit.c:882 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1040 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff0e2c14089 Code: Unable to access opcode bytes at 0x7ff0e2c1405f. RSP: 002b:00007ffe69e64ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff0e2c14089 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 00007ff0e2c8f390 R08: ffffffffffffffb8 R09: 0000000000000006 R10: 000000007ffff000 R11: 0000000000000246 R12: 00007ff0e2c8f390 R13: 0000000000000000 R14: 00007ff0e2c8fde0 R15: 00007ff0e2be5070 </TASK> Allocated by task 5249: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xaa3/0x2bb0 kernel/exit.c:882 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1040 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 12: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2250 [inline] slab_free mm/slub.c:4474 [inline] kfree+0x12a/0x3b0 mm/slub.c:4595 netfs_delete_buffer_head+0xa6/0x100 fs/netfs/misc.c:59 netfs_writeback_unlock_folios fs/netfs/write_collect.c:139 [inline] netfs_collect_write_results fs/netfs/write_collect.c:493 [inline] netfs_write_collection_worker+0x20f9/0x4f80 fs/netfs/write_collect.c:551 process_one_work+0x9c8/0x1b40 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3393 kthread+0x2c4/0x3a0 kernel/kthread.c:389 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff88802a63dc00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 288 bytes inside of freed 512-byte region [ffff88802a63dc00, ffff88802a63de00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a63c head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xfdffffff(slab) raw: 00fff00000000040 ffff88801ac41c80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000040 ffff88801ac41c80 dead000000000122 0000000000000000 head: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000002 ffffea0000a98f01 ffffffffffffffff 0000000000000000 head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5249, tgid 5249 (syz-executor341), ts 139218928620, free_ts 130646507944 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1500 prep_new_page mm/page_alloc.c:1508 [inline] get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3446 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4702 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x4e/0xf0 mm/slub.c:2319 allocate_slab mm/slub.c:2482 [inline] new_slab+0x84/0x260 mm/slub.c:2535 ___slab_alloc+0xdac/0x1870 mm/slub.c:3721 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3811 __slab_alloc_node mm/slub.c:3864 [inline] slab_alloc_node mm/slub.c:4026 [inline] __kmalloc_cache_noprof+0x2b4/0x300 mm/slub.c:4185 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 page last free pid 4682 tgid 4682 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1101 [inline] free_unref_page+0x64a/0xe40 mm/page_alloc.c:2619 __put_partials+0x14c/0x170 mm/slub.c:3049 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3989 [inline] slab_alloc_node mm/slub.c:4038 [inline] kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4045 getname_flags.part.0+0x4c/0x550 fs/namei.c:139 getname_flags+0x93/0xf0 include/linux/audit.h:322 vfs_fstatat+0x86/0x160 fs/stat.c:340 __do_sys_newfstatat+0xa2/0x130 fs/stat.c:505 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802a63dc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a63dc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802a63dd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802a63dd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a63de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ================================================================== BUG: KASAN: slab-use-after-free in iov_iter_folioq_advance lib/iov_iter.c:540 [inline] BUG: KASAN: slab-use-after-free in iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 Read of size 8 at addr ffff88802a63f520 by task syz-executor341/5249 CPU: 1 UID: 0 PID: 5249 Comm: syz-executor341 Tainted: G B 6.11.0-syzkaller-02574-ga430d95c5efa #0 Tainted: [B]=BAD_PAGE Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 iov_iter_folioq_advance lib/iov_iter.c:540 [inline] iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 netfs_write_folio+0x745/0x18f0 fs/netfs/write_issue.c:481 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xaa3/0x2bb0 kernel/exit.c:882 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1040 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff0e2c14089 Code: Unable to access opcode bytes at 0x7ff0e2c1405f. RSP: 002b:00007ffe69e64ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff0e2c14089 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 00007ff0e2c8f390 R08: ffffffffffffffb8 R09: 0000000000000006 R10: 000000007ffff000 R11: 0000000000000246 R12: 00007ff0e2c8f390 R13: 0000000000000000 R14: 00007ff0e2c8fde0 R15: 00007ff0e2be5070 </TASK> Allocated by task 5249: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xaa3/0x2bb0 kernel/exit.c:882 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1040 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 12: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2250 [inline] slab_free mm/slub.c:4474 [inline] kfree+0x12a/0x3b0 mm/slub.c:4595 netfs_delete_buffer_head+0xa6/0x100 fs/netfs/misc.c:59 netfs_writeback_unlock_folios fs/netfs/write_collect.c:139 [inline] netfs_collect_write_results fs/netfs/write_collect.c:493 [inline] netfs_write_collection_worker+0x20f9/0x4f80 fs/netfs/write_collect.c:551 process_one_work+0x9c8/0x1b40 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3393 kthread+0x2c4/0x3a0 kernel/kthread.c:389 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff88802a63f400 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 288 bytes inside of freed 512-byte region [ffff88802a63f400, ffff88802a63f600) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a63c head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xfdffffff(slab) raw: 00fff00000000040 ffff88801ac41c80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000040 ffff88801ac41c80 dead000000000122 0000000000000000 head: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000002 ffffea0000a98f01 ffffffffffffffff 0000000000000000 head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5249, tgid 5249 (syz-executor341), ts 139218928620, free_ts 130646507944 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1500 prep_new_page mm/page_alloc.c:1508 [inline] get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3446 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4702 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x4e/0xf0 mm/slub.c:2319 allocate_slab mm/slub.c:2482 [inline] new_slab+0x84/0x260 mm/slub.c:2535 ___slab_alloc+0xdac/0x1870 mm/slub.c:3721 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3811 __slab_alloc_node mm/slub.c:3864 [inline] slab_alloc_node mm/slub.c:4026 [inline] __kmalloc_cache_noprof+0x2b4/0x300 mm/slub.c:4185 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 page last free pid 4682 tgid 4682 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1101 [inline] free_unref_page+0x64a/0xe40 mm/page_alloc.c:2619 __put_partials+0x14c/0x170 mm/slub.c:3049 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3989 [inline] slab_alloc_node mm/slub.c:4038 [inline] kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4045 getname_flags.part.0+0x4c/0x550 fs/namei.c:139 getname_flags+0x93/0xf0 include/linux/audit.h:322 vfs_fstatat+0x86/0x160 fs/stat.c:340 __do_sys_newfstatat+0xa2/0x130 fs/stat.c:505 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802a63f400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a63f480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802a63f500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802a63f580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802a63f600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== ================================================================== BUG: KASAN: slab-use-after-free in iov_iter_folioq_advance lib/iov_iter.c:540 [inline] BUG: KASAN: slab-use-after-free in iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 Read of size 8 at addr ffff88802c8aad20 by task syz-executor341/5249 CPU: 1 UID: 0 PID: 5249 Comm: syz-executor341 Tainted: G B 6.11.0-syzkaller-02574-ga430d95c5efa #0 Tainted: [B]=BAD_PAGE Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:93 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119 print_address_description mm/kasan/report.c:377 [inline] print_report+0xc3/0x620 mm/kasan/report.c:488 kasan_report+0xd9/0x110 mm/kasan/report.c:601 iov_iter_folioq_advance lib/iov_iter.c:540 [inline] iov_iter_advance+0x677/0x6c0 lib/iov_iter.c:576 netfs_write_folio+0x745/0x18f0 fs/netfs/write_issue.c:481 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xaa3/0x2bb0 kernel/exit.c:882 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1040 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff0e2c14089 Code: Unable to access opcode bytes at 0x7ff0e2c1405f. RSP: 002b:00007ffe69e64ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff0e2c14089 RDX: 000000000000003c RSI: 00000000000000e7 RDI: 0000000000000000 RBP: 00007ff0e2c8f390 R08: ffffffffffffffb8 R09: 0000000000000006 R10: 000000007ffff000 R11: 0000000000000246 R12: 00007ff0e2c8f390 R13: 0000000000000000 R14: 00007ff0e2c8fde0 R15: 00007ff0e2be5070 </TASK> Allocated by task 5249: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:387 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 task_work_run+0x151/0x250 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xaa3/0x2bb0 kernel/exit.c:882 do_group_exit+0xd3/0x2a0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1040 x64_sys_call+0x14a9/0x16a0 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 11: kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2250 [inline] slab_free mm/slub.c:4474 [inline] kfree+0x12a/0x3b0 mm/slub.c:4595 netfs_delete_buffer_head+0xa6/0x100 fs/netfs/misc.c:59 netfs_writeback_unlock_folios fs/netfs/write_collect.c:139 [inline] netfs_collect_write_results fs/netfs/write_collect.c:493 [inline] netfs_write_collection_worker+0x20f9/0x4f80 fs/netfs/write_collect.c:551 process_one_work+0x9c8/0x1b40 kernel/workqueue.c:3231 process_scheduled_works kernel/workqueue.c:3312 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3393 kthread+0x2c4/0x3a0 kernel/kthread.c:389 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 The buggy address belongs to the object at ffff88802c8aac00 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 288 bytes inside of freed 512-byte region [ffff88802c8aac00, ffff88802c8aae00) The buggy address belongs to the physical page: page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2c8a8 head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff) page_type: 0xfdffffff(slab) raw: 00fff00000000040 ffff88801ac41c80 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000040 ffff88801ac41c80 dead000000000122 0000000000000000 head: 0000000000000000 0000000080100010 00000001fdffffff 0000000000000000 head: 00fff00000000002 ffffea0000b22a01 ffffffffffffffff 0000000000000000 head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5249, tgid 5249 (syz-executor341), ts 141121433556, free_ts 130792291213 set_page_owner include/linux/page_owner.h:32 [inline] post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1500 prep_new_page mm/page_alloc.c:1508 [inline] get_page_from_freelist+0x1351/0x2e50 mm/page_alloc.c:3446 __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4702 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline] alloc_pages_node_noprof include/linux/gfp.h:296 [inline] alloc_slab_page+0x4e/0xf0 mm/slub.c:2319 allocate_slab mm/slub.c:2482 [inline] new_slab+0x84/0x260 mm/slub.c:2535 ___slab_alloc+0xdac/0x1870 mm/slub.c:3721 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3811 __slab_alloc_node mm/slub.c:3864 [inline] slab_alloc_node mm/slub.c:4026 [inline] __kmalloc_cache_noprof+0x2b4/0x300 mm/slub.c:4185 kmalloc_noprof include/linux/slab.h:690 [inline] netfs_buffer_append_folio+0x181/0x750 fs/netfs/misc.c:25 netfs_write_folio+0x542/0x18f0 fs/netfs/write_issue.c:421 netfs_writepages+0x2ba/0xb90 fs/netfs/write_issue.c:541 do_writepages+0x1a6/0x7f0 mm/page-writeback.c:2683 filemap_fdatawrite_wbc mm/filemap.c:397 [inline] filemap_fdatawrite_wbc+0x148/0x1c0 mm/filemap.c:387 __filemap_fdatawrite_range+0xba/0x100 mm/filemap.c:430 v9fs_dir_release+0x429/0x590 fs/9p/vfs_dir.c:219 __fput+0x3f9/0xb60 fs/file_table.c:431 page last free pid 5243 tgid 5243 stack trace: reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1101 [inline] free_unref_page+0x64a/0xe40 mm/page_alloc.c:2619 __put_partials+0x14c/0x170 mm/slub.c:3049 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179 kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322 kasan_slab_alloc include/linux/kasan.h:201 [inline] slab_post_alloc_hook mm/slub.c:3989 [inline] slab_alloc_node mm/slub.c:4038 [inline] __kmalloc_cache_noprof+0x11e/0x300 mm/slub.c:4185 kmalloc_noprof include/linux/slab.h:690 [inline] kzalloc_noprof include/linux/slab.h:816 [inline] p9_fd_open net/9p/trans_fd.c:828 [inline] p9_fd_create+0x164/0x490 net/9p/trans_fd.c:1102 p9_client_create+0x879/0x1210 net/9p/client.c:1015 v9fs_session_init+0x1f8/0x1a80 fs/9p/v9fs.c:410 v9fs_mount+0xc6/0xa50 fs/9p/vfs_super.c:122 legacy_get_tree+0x10c/0x220 fs/fs_context.c:662 vfs_get_tree+0x92/0x380 fs/super.c:1800 do_new_mount fs/namespace.c:3507 [inline] path_mount+0x14e6/0x1f20 fs/namespace.c:3834 do_mount fs/namespace.c:3847 [inline] __do_sys_mount fs/namespace.c:4055 [inline] __se_sys_mount fs/namespace.c:4032 [inline] __x64_sys_mount+0x294/0x320 fs/namespace.c:4032 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Memory state around the buggy address: ffff88802c8aac00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802c8aac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88802c8aad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88802c8aad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88802c8aae00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkal...@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
