================================================================== BUG: KASAN: slab-use-after-free in gsm_cleanup_mux+0x799/0x810 drivers/tty/n_gsm.c:3052 Read of size 4 at addr ffff88814377700c by task syz-executor243/5008 CPU: 1 PID: 5008 Comm: syz-executor243 Not tainted 6.4.0-syzkaller-01406-ge8f75c0270d9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351 print_report mm/kasan/report.c:462 [inline] kasan_report+0x11c/0x130 mm/kasan/report.c:572 gsm_cleanup_mux+0x799/0x810 drivers/tty/n_gsm.c:3052 gsm_config drivers/tty/n_gsm.c:3327 [inline] gsmld_ioctl+0x4cd/0x1850 drivers/tty/n_gsm.c:3733 tty_ioctl+0x80b/0x16e0 drivers/tty/tty_io.c:2786 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f738b90ef09 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f738b89f1f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f738b9964d8 RCX: 00007f738b90ef09 RDX: 0000000020000040 RSI: 00000000404c4701 RDI: 0000000000000005 RBP: 00007f738b9964d0 R08: 00007f738b89f700 R09: 0000000000000000 R10: 00007f738b89f700 R11: 0000000000000246 R12: 00007f738b9964dc R13: 00007ffc8feebabf R14: 00007f738b89f300 R15: 0000000000022000 Allocated by task 4999: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] ____kasan_kmalloc mm/kasan/common.c:333 [inline] __kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383 kmalloc include/linux/slab.h:559 [inline] kzalloc include/linux/slab.h:680 [inline] gsm_dlci_alloc+0x46/0x7d0 drivers/tty/n_gsm.c:2618 gsm_activate_mux drivers/tty/n_gsm.c:3100 [inline] gsm_config drivers/tty/n_gsm.c:3355 [inline] gsmld_ioctl+0x846/0x1850 drivers/tty/n_gsm.c:3733 tty_ioctl+0x80b/0x16e0 drivers/tty/tty_io.c:2786 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Freed by task 4999: kasan_save_stack+0x22/0x40 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x40 mm/kasan/generic.c:521 ____kasan_slab_free mm/kasan/common.c:236 [inline] ____kasan_slab_free+0x160/0x1c0 mm/kasan/common.c:200 kasan_slab_free include/linux/kasan.h:162 [inline] slab_free_hook mm/slub.c:1781 [inline] slab_free_freelist_hook+0x8b/0x1c0 mm/slub.c:1807 slab_free mm/slub.c:3786 [inline] __kmem_cache_free+0xaf/0x2d0 mm/slub.c:3799 tty_port_destructor drivers/tty/tty_port.c:296 [inline] kref_put include/linux/kref.h:65 [inline] tty_port_put+0x15c/0x1c0 drivers/tty/tty_port.c:311 dlci_put drivers/tty/n_gsm.c:2681 [inline] gsm_dlci_release drivers/tty/n_gsm.c:2714 [inline] gsm_cleanup_mux+0x30a/0x810 drivers/tty/n_gsm.c:3074 gsm_config drivers/tty/n_gsm.c:3327 [inline] gsmld_ioctl+0x4cd/0x1850 drivers/tty/n_gsm.c:3733 tty_ioctl+0x80b/0x16e0 drivers/tty/tty_io.c:2786 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x19d/0x210 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The buggy address belongs to the object at ffff888143777000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 12 bytes inside of freed 2048-byte region [ffff888143777000, ffff888143777800) The buggy address belongs to the physical page: page:ffffea00050ddc00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x143770 head:ffffea00050ddc00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff) page_type: 0xffffffff() raw: 057ff00000010200 ffff888012442000 dead000000000100 dead000000000122 raw: 0000000000000000 0000000000080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 7098033790, free_ts 0 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x2db/0x350 mm/page_alloc.c:1744 prep_new_page mm/page_alloc.c:1751 [inline] get_page_from_freelist+0xf41/0x2c00 mm/page_alloc.c:3523 __alloc_pages+0x1cb/0x4a0 mm/page_alloc.c:4794 alloc_page_interleave+0x1e/0x200 mm/mempolicy.c:2112 alloc_pages+0x233/0x270 mm/mempolicy.c:2274 alloc_slab_page mm/slub.c:1851 [inline] allocate_slab+0x25f/0x390 mm/slub.c:1998 new_slab mm/slub.c:2051 [inline] ___slab_alloc+0xa91/0x1400 mm/slub.c:3192 __slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3291 __slab_alloc_node mm/slub.c:3344 [inline] slab_alloc_node mm/slub.c:3441 [inline] __kmem_cache_alloc_node+0x136/0x320 mm/slub.c:3490 kmalloc_trace+0x26/0xe0 mm/slab_common.c:1057 kmalloc include/linux/slab.h:559 [inline] kzalloc include/linux/slab.h:680 [inline] vidtv_demod_i2c_probe+0x6e/0x8a0 drivers/media/test-drivers/vidtv/vidtv_demod.c:421 i2c_device_probe+0x4ca/0xb60 drivers/i2c/i2c-core-base.c:565 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x240/0xca0 drivers/base/dd.c:658 __driver_probe_device+0x1df/0x4b0 drivers/base/dd.c:798 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:828 __device_attach_driver+0x1d4/0x2e0 drivers/base/dd.c:956 page_owner free stack trace missing Memory state around the buggy address: ffff888143776f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888143776f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888143777000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888143777080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888143777100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================