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* [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert
@ 2025-05-11 21:42 syzbot
  2025-05-14 13:05 ` syzbot
  0 siblings, 1 reply; 5+ messages in thread
From: syzbot @ 2025-05-11 21:42 UTC (permalink / raw)
  To: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

Hello,

syzbot found the following issue on:

HEAD commit:    d76bb1ebb558 Merge tag 'erofs-for-6.15-rc6-fixes' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=178a8670580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c4b1a03f36d77776
dashboard link: https://syzkaller.appspot.com/bug?extid=25b83a6f2c702075fcbc
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/2860fea791b5/disk-d76bb1eb.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6ad835ce04a2/vmlinux-d76bb1eb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6c0ebeae233a/bzImage-d76bb1eb.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+25b83a6f2c702075fcbc@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_revert lib/iov_iter.c:633 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611
Read of size 4 at addr ffff8880307a4678 by task kworker/u8:9/3466

CPU: 0 UID: 0 PID: 3466 Comm: kworker/u8:9 Not tainted 6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_revert lib/iov_iter.c:633 [inline]
 iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611
 netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline]
 netfs_retry_writes+0x166d/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 32 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880307a4fc0 pfn:0x307a4
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88801b441780 ffffea0000c9f9d0 ffffea0001f01990
raw: ffff8880307a4fc0 0000000000400038 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                                ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_revert lib/iov_iter.c:633 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x521/0x5a0 lib/iov_iter.c:611
Read of size 4 at addr ffff8880307a4668 by task kworker/u8:9/3466

CPU: 0 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_revert lib/iov_iter.c:633 [inline]
 iov_iter_revert+0x521/0x5a0 lib/iov_iter.c:611
 netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline]
 netfs_retry_writes+0x166d/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880307a4fc0 pfn:0x307a4
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88801b441780 ffffea0000c9f9d0 ffffea0001f01990
raw: ffff8880307a4fc0 0000000000400038 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                          ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_revert lib/iov_iter.c:633 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x521/0x5a0 lib/iov_iter.c:611
Read of size 4 at addr ffff8880307a4658 by task kworker/u8:9/3466

CPU: 1 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_revert lib/iov_iter.c:633 [inline]
 iov_iter_revert+0x521/0x5a0 lib/iov_iter.c:611
 netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline]
 netfs_retry_writes+0x166d/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880307a4fc0 pfn:0x307a4
flags: 0xfff00000000200(workingset|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000200 ffff88801b441780 ffffea0000c9f9d0 ffffea0001f01990
raw: ffff8880307a4fc0 0000000000400038 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_bvec_advance lib/iov_iter.c:504 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_advance+0x652/0x6c0 lib/iov_iter.c:576
Read of size 4 at addr ffff8880307a4658 by task kworker/u8:9/3466

CPU: 0 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_bvec_advance lib/iov_iter.c:504 [inline]
 iov_iter_advance+0x652/0x6c0 lib/iov_iter.c:576
 netfs_reissue_write+0x13d/0x240 fs/netfs/write_issue.c:250
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: 00 00 00 fc fc fc fc fc 00 00 00 fc fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_bvec_advance lib/iov_iter.c:504 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_advance+0x652/0x6c0 lib/iov_iter.c:576
Read of size 4 at addr ffff8880307a4668 by task kworker/u8:9/3466

CPU: 0 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_bvec_advance lib/iov_iter.c:504 [inline]
 iov_iter_advance+0x652/0x6c0 lib/iov_iter.c:576
 netfs_reissue_write+0x13d/0x240 fs/netfs/write_issue.c:250
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 16 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                          ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_bvec_advance lib/iov_iter.c:504 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_advance+0x652/0x6c0 lib/iov_iter.c:576
Read of size 4 at addr ffff8880307a4678 by task kworker/u8:9/3466

CPU: 1 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_bvec_advance lib/iov_iter.c:504 [inline]
 iov_iter_advance+0x652/0x6c0 lib/iov_iter.c:576
 netfs_reissue_write+0x13d/0x240 fs/netfs/write_issue.c:250
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 32 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                                ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: wild-memory-access in memcpy_from_iter lib/iov_iter.c:73 [inline]
BUG: KASAN: wild-memory-access in iterate_bvec include/linux/iov_iter.h:123 [inline]
BUG: KASAN: wild-memory-access in iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
BUG: KASAN: wild-memory-access in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KASAN: wild-memory-access in __copy_from_iter lib/iov_iter.c:249 [inline]
BUG: KASAN: wild-memory-access in _copy_from_iter+0x8c9/0x15b0 lib/iov_iter.c:260
Read of size 50 at addr ffe728a1399fbe06 by task kworker/u8:9/3466

CPU: 0 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105
 memcpy_from_iter lib/iov_iter.c:73 [inline]
 iterate_bvec include/linux/iov_iter.h:123 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 _copy_from_iter+0x8c9/0x15b0 lib/iov_iter.c:260
 copy_from_iter include/linux/uio.h:228 [inline]
 copy_from_iter_full include/linux/uio.h:245 [inline]
 pdu_write_u net/9p/protocol.c:234 [inline]
 p9pdu_vwritef+0x2da/0x1d30 net/9p/protocol.c:614
 p9_client_prepare_req+0x247/0x4d0 net/9p/client.c:651
 p9_client_rpc+0x1c4/0xc50 net/9p/client.c:691
 p9_client_write+0x245/0x6f0 net/9p/client.c:1648
 v9fs_issue_write+0xe3/0x1b0 fs/9p/vfs_addr.c:59
 netfs_do_issue_write+0x95/0x110 fs/netfs/write_issue.c:239
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iterate_bvec include/linux/iov_iter.h:117 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KASAN: slab-out-of-bounds in __copy_from_iter lib/iov_iter.c:249 [inline]
BUG: KASAN: slab-out-of-bounds in _copy_from_iter+0x132f/0x15b0 lib/iov_iter.c:260
Read of size 4 at addr ffff8880307a465c by task kworker/u8:9/3466

CPU: 1 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iterate_bvec include/linux/iov_iter.h:117 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 _copy_from_iter+0x132f/0x15b0 lib/iov_iter.c:260
 copy_from_iter include/linux/uio.h:228 [inline]
 copy_from_iter_full include/linux/uio.h:245 [inline]
 pdu_write_u net/9p/protocol.c:234 [inline]
 p9pdu_vwritef+0x2da/0x1d30 net/9p/protocol.c:614
 p9_client_prepare_req+0x247/0x4d0 net/9p/client.c:651
 p9_client_rpc+0x1c4/0xc50 net/9p/client.c:691
 p9_client_write+0x245/0x6f0 net/9p/client.c:1648
 v9fs_issue_write+0xe3/0x1b0 fs/9p/vfs_addr.c:59
 netfs_do_issue_write+0x95/0x110 fs/netfs/write_issue.c:239
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 4 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iterate_bvec include/linux/iov_iter.h:120 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KASAN: slab-out-of-bounds in __copy_from_iter lib/iov_iter.c:249 [inline]
BUG: KASAN: slab-out-of-bounds in _copy_from_iter+0x1459/0x15b0 lib/iov_iter.c:260
Read of size 4 at addr ffff8880307a4658 by task kworker/u8:9/3466

CPU: 1 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iterate_bvec include/linux/iov_iter.h:120 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 _copy_from_iter+0x1459/0x15b0 lib/iov_iter.c:260
 copy_from_iter include/linux/uio.h:228 [inline]
 copy_from_iter_full include/linux/uio.h:245 [inline]
 pdu_write_u net/9p/protocol.c:234 [inline]
 p9pdu_vwritef+0x2da/0x1d30 net/9p/protocol.c:614
 p9_client_prepare_req+0x247/0x4d0 net/9p/client.c:651
 p9_client_rpc+0x1c4/0xc50 net/9p/client.c:691
 p9_client_write+0x245/0x6f0 net/9p/client.c:1648
 v9fs_issue_write+0xe3/0x1b0 fs/9p/vfs_addr.c:59
 netfs_do_issue_write+0x95/0x110 fs/netfs/write_issue.c:239
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iterate_bvec include/linux/iov_iter.h:129 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KASAN: slab-out-of-bounds in __copy_from_iter lib/iov_iter.c:249 [inline]
BUG: KASAN: slab-out-of-bounds in _copy_from_iter+0x1416/0x15b0 lib/iov_iter.c:260
Read of size 4 at addr ffff8880307a4658 by task kworker/u8:9/3466

CPU: 1 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iterate_bvec include/linux/iov_iter.h:129 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 _copy_from_iter+0x1416/0x15b0 lib/iov_iter.c:260
 copy_from_iter include/linux/uio.h:228 [inline]
 copy_from_iter_full include/linux/uio.h:245 [inline]
 pdu_write_u net/9p/protocol.c:234 [inline]
 p9pdu_vwritef+0x2da/0x1d30 net/9p/protocol.c:614
 p9_client_prepare_req+0x247/0x4d0 net/9p/client.c:651
 p9_client_rpc+0x1c4/0xc50 net/9p/client.c:691
 p9_client_write+0x245/0x6f0 net/9p/client.c:1648
 v9fs_issue_write+0xe3/0x1b0 fs/9p/vfs_addr.c:59
 netfs_do_issue_write+0x95/0x110 fs/netfs/write_issue.c:239
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __kmalloc_cache_noprof+0xfb/0x3e0 mm/slub.c:4353
 kmalloc_noprof include/linux/slab.h:905 [inline]
 slab_free_hook mm/slub.c:2332 [inline]
 slab_free mm/slub.c:4642 [inline]
 kmem_cache_free+0x148/0x4d0 mm/slub.c:4744
 exit_mmap+0x511/0xb90 mm/mmap.c:1309
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
page last free pid 5741 tgid 5741 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 tlb_batch_list_free mm/mmu_gather.c:159 [inline]
 tlb_finish_mmu+0x237/0x7b0 mm/mmu_gather.c:499
 exit_mmap+0x403/0xb90 mm/mmap.c:1297
 __mmput+0x12a/0x410 kernel/fork.c:1379
 mmput+0x62/0x70 kernel/fork.c:1401
 exit_mm kernel/exit.c:589 [inline]
 do_exit+0x9d1/0x2c30 kernel/exit.c:940
 do_group_exit+0xd3/0x2a0 kernel/exit.c:1102
 __do_sys_exit_group kernel/exit.c:1113 [inline]
 __se_sys_exit_group kernel/exit.c:1111 [inline]
 __x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1111
 x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff8880307a4500: 00 00 00 00 fc fc fc fc fa fb fb fb fc fc fc fc
 ffff8880307a4580: fa fb fb fb fc fc fc fc fa fb fb fb fc fc fc fc
>ffff8880307a4600: 00 00 00 00 fc fc fc fc 00 00 00 fc fc fc fc fc
                                                    ^
 ffff8880307a4680: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
 ffff8880307a4700: 00 00 00 00 fc fc fc fc 00 00 00 00 fc fc fc fc
==================================================================
==================================================================
BUG: KASAN: slab-out-of-bounds in iterate_bvec include/linux/iov_iter.h:117 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
BUG: KASAN: slab-out-of-bounds in iterate_and_advance include/linux/iov_iter.h:328 [inline]
BUG: KASAN: slab-out-of-bounds in __copy_from_iter lib/iov_iter.c:249 [inline]
BUG: KASAN: slab-out-of-bounds in _copy_from_iter+0x132f/0x15b0 lib/iov_iter.c:260
Read of size 4 at addr ffff8880307a466c by task kworker/u8:9/3466

CPU: 0 UID: 0 PID: 3466 Comm: kworker/u8:9 Tainted: G    B               6.15.0-rc5-syzkaller-00043-gd76bb1ebb558 #0 PREEMPT(full) 
Tainted: [B]=BAD_PAGE
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iterate_bvec include/linux/iov_iter.h:117 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:304 [inline]
 iterate_and_advance include/linux/iov_iter.h:328 [inline]
 __copy_from_iter lib/iov_iter.c:249 [inline]
 _copy_from_iter+0x132f/0x15b0 lib/iov_iter.c:260
 copy_from_iter include/linux/uio.h:228 [inline]
 copy_from_iter_full include/linux/uio.h:245 [inline]
 pdu_write_u net/9p/protocol.c:234 [inline]
 p9pdu_vwritef+0x2da/0x1d30 net/9p/protocol.c:614
 p9_client_prepare_req+0x247/0x4d0 net/9p/client.c:651
 p9_client_rpc+0x1c4/0xc50 net/9p/client.c:691
 p9_client_write+0x245/0x6f0 net/9p/client.c:1648
 v9fs_issue_write+0xe3/0x1b0 fs/9p/vfs_addr.c:59
 netfs_do_issue_write+0x95/0x110 fs/netfs/write_issue.c:239
 netfs_retry_write_stream fs/netfs/write_retry.c:46 [inline]
 netfs_retry_writes+0x168a/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 970:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kmalloc_noprof include/linux/slab.h:905 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 nsim_fib6_rt_nh_add+0x4a/0x290 drivers/net/netdevsim/fib.c:500
 nsim_fib6_rt_create drivers/net/netdevsim/fib.c:562 [inline]
 nsim_fib6_rt_insert drivers/net/netdevsim/fib.c:752 [inline]
 nsim_fib6_event drivers/net/netdevsim/fib.c:856 [inline]
 nsim_fib_event drivers/net/netdevsim/fib.c:889 [inline]
 nsim_fib_event_work+0x196a/0x2e80 drivers/net/netdevsim/fib.c:1493
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c5/0x780 kernel/kthread.c:464
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880307a4640
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 20 bytes to the right of
 allocated 24-byte region [ffff8880307a4640, ffff8880307a4658)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x307a4
anon flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b441780 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000400040 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52800(GFP_NOWAIT|__GFP_NORETRY|__GFP_COMP), pid 5741, tgid 5741 (dhcpcd-run-hook), ts 89207943594, free_ts 89206634714
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:261

---
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 syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert
  2025-05-11 21:42 [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert syzbot
@ 2025-05-14 13:05 ` syzbot
  2025-05-16 19:03   ` David Howells
  2025-05-16 22:37   ` David Howells
  0 siblings, 2 replies; 5+ messages in thread
From: syzbot @ 2025-05-14 13:05 UTC (permalink / raw)
  To: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

syzbot has found a reproducer for the following issue on:

HEAD commit:    9f35e33144ae x86/its: Fix build errors when CONFIG_MODULES=n
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16388e70580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c9b33a466dfee330
dashboard link: https://syzkaller.appspot.com/bug?extid=25b83a6f2c702075fcbc
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=1193a6f4580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16899cd4580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-9f35e331.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b18c4a4e3b8e/vmlinux-9f35e331.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ae7ab8362f22/bzImage-9f35e331.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+25b83a6f2c702075fcbc@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in iov_iter_revert lib/iov_iter.c:633 [inline]
BUG: KASAN: slab-out-of-bounds in iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611
Read of size 4 at addr ffff88802912a0b8 by task kworker/u32:7/1147

CPU: 1 UID: 0 PID: 1147 Comm: kworker/u32:7 Not tainted 6.15.0-rc6-syzkaller-00052-g9f35e33144ae #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Workqueue: events_unbound netfs_write_collection_worker
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:408 [inline]
 print_report+0xc3/0x670 mm/kasan/report.c:521
 kasan_report+0xe0/0x110 mm/kasan/report.c:634
 iov_iter_revert lib/iov_iter.c:633 [inline]
 iov_iter_revert+0x443/0x5a0 lib/iov_iter.c:611
 netfs_retry_write_stream fs/netfs/write_retry.c:44 [inline]
 netfs_retry_writes+0x166d/0x1a50 fs/netfs/write_retry.c:231
 netfs_collect_write_results fs/netfs/write_collect.c:352 [inline]
 netfs_write_collection_worker+0x23fd/0x3830 fs/netfs/write_collect.c:374
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 5936:
 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:377 [inline]
 __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4339
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 tomoyo_encode2+0x100/0x3e0 security/tomoyo/realpath.c:45
 tomoyo_encode+0x29/0x50 security/tomoyo/realpath.c:80
 tomoyo_realpath_from_path+0x18f/0x6e0 security/tomoyo/realpath.c:283
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x274/0x460 security/tomoyo/file.c:822
 security_file_truncate+0x84/0x1e0 security/security.c:3146
 handle_truncate fs/namei.c:3499 [inline]
 do_open fs/namei.c:3884 [inline]
 path_openat+0xc85/0x2d40 fs/namei.c:4039
 do_filp_open+0x20b/0x470 fs/namei.c:4066
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_creat fs/open.c:1522 [inline]
 __se_sys_creat fs/open.c:1516 [inline]
 __x64_sys_creat+0xcc/0x120 fs/open.c:1516
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5936:
 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:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2380 [inline]
 slab_free mm/slub.c:4642 [inline]
 kfree+0x2b6/0x4d0 mm/slub.c:4841
 tomoyo_path_perm+0x29a/0x460 security/tomoyo/file.c:842
 security_file_truncate+0x84/0x1e0 security/security.c:3146
 handle_truncate fs/namei.c:3499 [inline]
 do_open fs/namei.c:3884 [inline]
 path_openat+0xc85/0x2d40 fs/namei.c:4039
 do_filp_open+0x20b/0x470 fs/namei.c:4066
 do_sys_openat2+0x11b/0x1d0 fs/open.c:1429
 do_sys_open fs/open.c:1444 [inline]
 __do_sys_creat fs/open.c:1522 [inline]
 __se_sys_creat fs/open.c:1516 [inline]
 __x64_sys_creat+0xcc/0x120 fs/open.c:1516
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802912a0a0
 which belongs to the cache kmalloc-16 of size 16
The buggy address is located 8 bytes to the right of
 allocated 16-byte region [ffff88802912a0a0, ffff88802912a0b0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2912a
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000000 ffff88801b442640 dead000000000100 dead000000000122
raw: 0000000000000000 0000000080800080 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c00(GFP_NOIO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 1, tgid 1 (swapper/0), ts 13358119373, free_ts 11984335158
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x181/0x1b0 mm/page_alloc.c:1718
 prep_new_page mm/page_alloc.c:1726 [inline]
 get_page_from_freelist+0x135c/0x3920 mm/page_alloc.c:3688
 __alloc_frozen_pages_noprof+0x263/0x23a0 mm/page_alloc.c:4970
 alloc_pages_mpol+0x1fb/0x550 mm/mempolicy.c:2301
 alloc_slab_page mm/slub.c:2450 [inline]
 allocate_slab mm/slub.c:2618 [inline]
 new_slab+0x244/0x340 mm/slub.c:2672
 ___slab_alloc+0xd9c/0x1940 mm/slub.c:3858
 __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3948
 __slab_alloc_node mm/slub.c:4023 [inline]
 slab_alloc_node mm/slub.c:4184 [inline]
 __do_kmalloc_node mm/slub.c:4326 [inline]
 __kmalloc_noprof+0x2f2/0x510 mm/slub.c:4339
 kmalloc_noprof include/linux/slab.h:909 [inline]
 usb_cache_string+0xab/0x150 drivers/usb/core/message.c:1032
 usb_enumerate_device drivers/usb/core/hub.c:2508 [inline]
 usb_new_device+0x238/0x1a20 drivers/usb/core/hub.c:2633
 register_root_hub+0x299/0x730 drivers/usb/core/hcd.c:994
 usb_add_hcd+0xaf2/0x1730 drivers/usb/core/hcd.c:2976
 dummy_hcd_probe+0x15c/0x380 drivers/usb/gadget/udc/dummy_hcd.c:2693
 platform_probe+0x102/0x1f0 drivers/base/platform.c:1404
 call_driver_probe drivers/base/dd.c:579 [inline]
 really_probe+0x23e/0xa90 drivers/base/dd.c:657
 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:799
page last free pid 838 tgid 838 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1262 [inline]
 __free_frozen_pages+0x69d/0xff0 mm/page_alloc.c:2725
 vfree+0x176/0x960 mm/vmalloc.c:3384
 delayed_vfree_work+0x56/0x70 mm/vmalloc.c:3304
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Memory state around the buggy address:
 ffff888029129f80: 00 02 fc fc 00 04 fc fc 00 04 fc fc 00 04 fc fc
 ffff88802912a000: 00 05 fc fc 00 00 fc fc 00 01 fc fc 00 01 fc fc
>ffff88802912a080: 00 01 fc fc fa fb fc fc 00 00 fc fc 00 05 fc fc
                                        ^
 ffff88802912a100: 00 01 fc fc fa fb fc fc fa fb fc fc 00 00 fc fc
 ffff88802912a180: 00 01 fc fc 00 00 fc fc 00 01 fc fc 00 01 fc fc
==================================================================


---
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.

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert
  2025-05-14 13:05 ` syzbot
@ 2025-05-16 19:03   ` David Howells
  2025-05-16 22:37   ` David Howells
  1 sibling, 0 replies; 5+ messages in thread
From: David Howells @ 2025-05-16 19:03 UTC (permalink / raw)
  To: syzbot; +Cc: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

Note that the mount() syscall in the test program doesn't seem to work if
SELinux is enabled.

David


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert
  2025-05-14 13:05 ` syzbot
  2025-05-16 19:03   ` David Howells
@ 2025-05-16 22:37   ` David Howells
  2025-05-16 22:58     ` syzbot
  1 sibling, 1 reply; 5+ messages in thread
From: David Howells @ 2025-05-16 22:37 UTC (permalink / raw)
  To: syzbot; +Cc: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.15-rc6

commit 4f771b49180c404f518c686cdff749ff81f3cc77
Author: David Howells <dhowells@redhat.com>
Date:   Fri May 16 23:35:25 2025 +0100

    netfs: Fix oops in write-retry from mis-resetting the subreq iterator

diff --git a/fs/netfs/write_retry.c b/fs/netfs/write_retry.c
index f75e0e8c02cf..9d1d8a8bab72 100644
--- a/fs/netfs/write_retry.c
+++ b/fs/netfs/write_retry.c
@@ -39,9 +39,10 @@ static void netfs_retry_write_stream(struct netfs_io_request *wreq,
 			if (test_bit(NETFS_SREQ_FAILED, &subreq->flags))
 				break;
 			if (__test_and_clear_bit(NETFS_SREQ_NEED_RETRY, &subreq->flags)) {
-				struct iov_iter source = subreq->io_iter;
+				struct iov_iter source;
 
-				iov_iter_revert(&source, subreq->len - source.count);
+				netfs_reset_iter(subreq);
+				source = subreq->io_iter;
 				netfs_get_subrequest(subreq, netfs_sreq_trace_get_resubmit);
 				netfs_reissue_write(stream, subreq, &source);
 			}


^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert
  2025-05-16 22:37   ` David Howells
@ 2025-05-16 22:58     ` syzbot
  0 siblings, 0 replies; 5+ messages in thread
From: syzbot @ 2025-05-16 22:58 UTC (permalink / raw)
  To: dhowells, linux-fsdevel, linux-kernel, netfs, pc, syzkaller-bugs

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+25b83a6f2c702075fcbc@syzkaller.appspotmail.com
Tested-by: syzbot+25b83a6f2c702075fcbc@syzkaller.appspotmail.com

Tested on:

commit:         82f2b0b9 Linux 6.15-rc6
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git v6.15-rc6
console output: https://syzkaller.appspot.com/x/log.txt?x=11960ef4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=753a0ce88f56915c
dashboard link: https://syzkaller.appspot.com/bug?extid=25b83a6f2c702075fcbc
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
patch:          https://syzkaller.appspot.com/x/patch.diff?x=174022d4580000

Note: testing is done by a robot and is best-effort only.

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2025-05-16 22:58 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-05-11 21:42 [syzbot] [netfs?] KASAN: slab-out-of-bounds Read in iov_iter_revert syzbot
2025-05-14 13:05 ` syzbot
2025-05-16 19:03   ` David Howells
2025-05-16 22:37   ` David Howells
2025-05-16 22:58     ` syzbot

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