Re: KASAN: use-after-free Write in _free_event
Hi everyone, I meet this bug two times, does anyone has idea to fix this issue ? (See attachments) == BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline] BUG: KASAN: use-after-free in put_task_struct include/linux/sched/task.h:95 [inline] BUG: KASAN: use-after-free in _free_event+0x2c4/0xfe0 kernel/events/core.c:4452 Write of size 4 at addr 8883780cd0a0 by task syz-executor0/9553 CPU: 3 PID: 9553 Comm: syz-executor0 Not tainted 4.19.18-514.55.6.9.x86_64+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xca/0x13e lib/dump_stack.c:113 print_address_description+0x79/0x330 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x18a/0x2e0 mm/kasan/report.c:412 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline] put_task_struct include/linux/sched/task.h:95 [inline] _free_event+0x2c4/0xfe0 kernel/events/core.c:4452 free_event+0x41/0xa0 kernel/events/core.c:4473 perf_event_release_kernel+0x43b/0xc70 kernel/events/core.c:4634 perf_release+0x33/0x40 kernel/events/core.c:4648 __fput+0x27f/0x7f0 fs/file_table.c:278 task_work_run+0x136/0x1b0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x850/0x2b90 kernel/exit.c:867 do_group_exit+0x106/0x2f0 kernel/exit.c:970 get_signal+0x62b/0x1740 kernel/signal.c:2513 do_signal+0x94/0x16a0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x108/0x1d0 arch/x86/entry/common.c:162 prepare_exit_to_usermode+0x27b/0x2f0 arch/x86/entry/common.c:197 retint_user+0x8/0x18 RIP: 0033:0x4021b7 Code: Bad RIP value. RSP: 002b:7fa7cb40cb30 EFLAGS: 00010202 RAX: RBX: 000b RCX: 00462589 RDX: 7fa7cb40cb40 RSI: ffb8 RDI: 000b RBP: R08: R09: R10: R11: 0246 R12: R13: 004bc4cd R14: 006f4c70 R15: Allocated by task 9552: set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xa0/0xd0 mm/kasan/kasan.c:553 slab_post_alloc_hook mm/slab.h:444 [inline] slab_alloc_node mm/slub.c:2706 [inline] kmem_cache_alloc_node+0xe3/0x2e0 mm/slub.c:2742 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:802 [inline] copy_process.part.26+0x1a98/0x6c70 kernel/fork.c:1707 copy_process kernel/fork.c:1664 [inline] _do_fork+0x1c6/0xe60 kernel/fork.c:2175 do_syscall_64+0xc8/0x580 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 9552: set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x12e/0x180 mm/kasan/kasan.c:521 slab_free_hook mm/slub.c:1371 [inline] slab_free_freelist_hook mm/slub.c:1398 [inline] slab_free mm/slub.c:2953 [inline] kmem_cache_free+0xbd/0x320 mm/slub.c:2969 copy_process.part.26+0x18d9/0x6c70 kernel/fork.c:2107 copy_process kernel/fork.c:1664 [inline] _do_fork+0x1c6/0xe60 kernel/fork.c:2175 do_syscall_64+0xc8/0x580 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at 8883780cd080 which belongs to the cache task_struct of size 9992 The buggy address is located 32 bytes inside of 9992-byte region [8883780cd080, 8883780cf788) The buggy address belongs to the page: page:ea000de03200 count:1 mapcount:0 mapping:888107d07a00 index:0x0 compound_mapcount: 0 flags: 0x2f80008100(slab|head) raw: 002f80008100 dead0100 dead0200 888107d07a00 raw: 80030003 0001 page dumped because: kasan: bad access detected Memory state around the buggy address: 8883780ccf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc 8883780cd000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >8883780cd080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ 8883780cd100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb 8883780cd180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb == On 2018/7/9 18:11, Alexander Shishkin wrote: > syzbot writes: > >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit:b2d44d145d2a Merge tag '4.18-rc3-smb3fixes' of git://git.s.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=178cf50c40 >> kernel config: https://syzkaller.appspot.com/x/.config?x=2ca6c7a31d407f86 >> dashboard link: https://syzkaller.appspot.com/bug?extid=a24c397a29ad22d86c98 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. > > Is there a chance of getting a reproducer for this one? > > Thanks, > -- > Al
Re: KASAN: use-after-free Write in _free_event
syzbot has found a reproducer for the following crash on: HEAD commit:092150a25cb7 Merge branch 'for-linus' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16627cc240 kernel config: https://syzkaller.appspot.com/x/.config?x=25856fac4e580aa7 dashboard link: https://syzkaller.appspot.com/bug?extid=a24c397a29ad22d86c98 compiler: gcc (GCC) 8.0.1 20180413 (experimental) syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=14d45afc40 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16dd496840 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a24c397a29ad22d86...@syzkaller.appspotmail.com == BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:222 [inline] BUG: KASAN: use-after-free in put_task_struct include/linux/sched/task.h:95 [inline] BUG: KASAN: use-after-free in _free_event+0x48d/0x1440 kernel/events/core.c:4451 Write of size 4 at addr 8801ab6360e0 by task syz-executor205/5237 CPU: 1 PID: 5237 Comm: syz-executor205 Not tainted 4.18.0-rc4+ #139 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:222 [inline] put_task_struct include/linux/sched/task.h:95 [inline] _free_event+0x48d/0x1440 kernel/events/core.c:4451 free_event+0xb4/0x180 kernel/events/core.c:4472 perf_event_release_kernel+0x7d5/0x1050 kernel/events/core.c:4633 perf_release+0x37/0x50 kernel/events/core.c:4647 __fput+0x355/0x8b0 fs/file_table.c:209 fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1b08/0x2750 kernel/exit.c:865 do_group_exit+0x177/0x440 kernel/exit.c:968 get_signal+0x88e/0x1970 kernel/signal.c:2468 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162 prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197 retint_user+0x8/0x18 RIP: 0033: (null) Code: Bad RIP value. RSP: 002b:2048 EFLAGS: 00010217 RAX: RBX: 006dbc24 RCX: 00445d89 RDX: 2100 RSI: 2040 RDI: RBP: R08: 2080 R09: R10: 2000 R11: 0246 R12: 006dbc20 R13: 0030656c69662f2e R14: 00408912 R15: 0006 Allocated by task 5236: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3644 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:779 [inline] copy_process.part.39+0x16b5/0x7220 kernel/fork.c:1641 copy_process kernel/fork.c:1616 [inline] _do_fork+0x291/0x12a0 kernel/fork.c:2099 __do_sys_clone kernel/fork.c:2206 [inline] __se_sys_clone kernel/fork.c:2200 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2200 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 5236: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 free_task_struct kernel/fork.c:162 [inline] free_task+0x16e/0x1f0 kernel/fork.c:390 copy_process.part.39+0x15c9/0x7220 kernel/fork.c:2034 copy_process kernel/fork.c:1616 [inline] _do_fork+0x291/0x12a0 kernel/fork.c:2099 __do_sys_clone kernel/fork.c:2206 [inline] __se_sys_clone kernel/fork.c:2200 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2200 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at 8801ab6360c0 which belongs to the cache task_struct of size 5952 The buggy address is located 32 bytes inside of 5952-byte region [8801ab6360c0, 8801ab637800) The buggy address belongs to the page: page:ea0006ad8d80 count:1 mapcount:0 mapping:8801da94b200 index:0x0 compound_mapcount: 0 flags: 0x2fffc008100(slab|head) raw: 02fffc008100 ea0006ad9008 ea00075f5888 8801da94b200 raw: 8801ab6360c0 000
Re: KASAN: use-after-free Write in _free_event
On Mon, Jul 9, 2018 at 12:11 PM, Alexander Shishkin wrote: > syzbot writes: > >> Hello, >> >> syzbot found the following crash on: >> >> HEAD commit:b2d44d145d2a Merge tag '4.18-rc3-smb3fixes' of git://git.s.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=178cf50c40 >> kernel config: https://syzkaller.appspot.com/x/.config?x=2ca6c7a31d407f86 >> dashboard link: https://syzkaller.appspot.com/bug?extid=a24c397a29ad22d86c98 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. > > Is there a chance of getting a reproducer for this one? There is a chance. Frequently syzbot finds a reproducer after some time. What's the chance in this case I don't know. Since it happened only once so far, probably not too high. But there seems to be a good hint in the KASAN report: task was freed right inside of fork/copy_process, probably some error happened, but it seems to have been registered in some global list already and perf_release discovered it there. Does it make sense? Was it registered? What should have been prevented the task alive at the time of access?
Re: KASAN: use-after-free Write in _free_event
syzbot writes: > Hello, > > syzbot found the following crash on: > > HEAD commit:b2d44d145d2a Merge tag '4.18-rc3-smb3fixes' of git://git.s.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=178cf50c40 > kernel config: https://syzkaller.appspot.com/x/.config?x=2ca6c7a31d407f86 > dashboard link: https://syzkaller.appspot.com/bug?extid=a24c397a29ad22d86c98 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. Is there a chance of getting a reproducer for this one? Thanks, -- Alex
KASAN: use-after-free Write in _free_event
Hello, syzbot found the following crash on: HEAD commit:b2d44d145d2a Merge tag '4.18-rc3-smb3fixes' of git://git.s.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=178cf50c40 kernel config: https://syzkaller.appspot.com/x/.config?x=2ca6c7a31d407f86 dashboard link: https://syzkaller.appspot.com/bug?extid=a24c397a29ad22d86c98 compiler: gcc (GCC) 8.0.1 20180413 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+a24c397a29ad22d86...@syzkaller.appspotmail.com == BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:222 [inline] BUG: KASAN: use-after-free in put_task_struct include/linux/sched/task.h:95 [inline] BUG: KASAN: use-after-free in _free_event+0x48d/0x1440 kernel/events/core.c:4451 Write of size 4 at addr 8801999ee2a0 by task syz-executor2/19286 CPU: 1 PID: 19286 Comm: syz-executor2 Not tainted 4.18.0-rc3+ #136 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 check_memory_region_inline mm/kasan/kasan.c:260 [inline] check_memory_region+0x13e/0x1b0 mm/kasan/kasan.c:267 kasan_check_write+0x14/0x20 mm/kasan/kasan.c:278 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:222 [inline] put_task_struct include/linux/sched/task.h:95 [inline] _free_event+0x48d/0x1440 kernel/events/core.c:4451 free_event+0xb4/0x180 kernel/events/core.c:4472 perf_event_release_kernel+0x7d5/0x1050 kernel/events/core.c:4633 perf_release+0x37/0x50 kernel/events/core.c:4647 __fput+0x355/0x8b0 fs/file_table.c:209 fput+0x15/0x20 fs/file_table.c:243 task_work_run+0x1ec/0x2a0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x1b08/0x2750 kernel/exit.c:865 do_group_exit+0x177/0x440 kernel/exit.c:968 get_signal+0x88e/0x1970 kernel/signal.c:2468 do_signal+0x9c/0x21c0 arch/x86/kernel/signal.c:816 exit_to_usermode_loop+0x2e0/0x370 arch/x86/entry/common.c:162 prepare_exit_to_usermode+0x342/0x3b0 arch/x86/entry/common.c:197 retint_user+0x8/0x18 RIP: 0033: (null) Code: Bad RIP value. RSP: 002b:2048 EFLAGS: 00010217 RAX: RBX: 7f62934726d4 RCX: 00455e29 RDX: 2100 RSI: 2040 RDI: RBP: 0072bea0 R08: 2080 R09: R10: 2000 R11: 0246 R12: R13: 004bbc2c R14: 004c8f48 R15: Allocated by task 19280: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490 kmem_cache_alloc_node+0x144/0x780 mm/slab.c:3644 alloc_task_struct_node kernel/fork.c:157 [inline] dup_task_struct kernel/fork.c:779 [inline] copy_process.part.39+0x16b5/0x7220 kernel/fork.c:1641 copy_process kernel/fork.c:1616 [inline] _do_fork+0x291/0x12a0 kernel/fork.c:2099 __do_sys_clone kernel/fork.c:2206 [inline] __se_sys_clone kernel/fork.c:2200 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2200 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 19280: save_stack+0x43/0xd0 mm/kasan/kasan.c:448 set_track mm/kasan/kasan.c:460 [inline] __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 __cache_free mm/slab.c:3498 [inline] kmem_cache_free+0x86/0x2d0 mm/slab.c:3756 free_task_struct kernel/fork.c:162 [inline] free_task+0x16e/0x1f0 kernel/fork.c:390 copy_process.part.39+0x15c9/0x7220 kernel/fork.c:2034 copy_process kernel/fork.c:1616 [inline] _do_fork+0x291/0x12a0 kernel/fork.c:2099 __do_sys_clone kernel/fork.c:2206 [inline] __se_sys_clone kernel/fork.c:2200 [inline] __x64_sys_clone+0xbf/0x150 kernel/fork.c:2200 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at 8801999ee280 which belongs to the cache task_struct(81:syz2) of size 5952 The buggy address is located 32 bytes inside of 5952-byte region [8801999ee280, 8801999ef9c0) The buggy address belongs to the page: page:ea0006667b80 count:1 mapcount:0 mapping:8801b0bb6300 index:0x0 compound_mapcount: 0 flags: 0x2fffc008100(slab|head) raw: 02fffc008100 ea00071a0888 8801ab65ce48 8801b0bb6300 raw: 8801999ee280 00010001 8801acaa4000 page dumped because: kasan: bad access detected page->mem
