Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: KASAN: null-ptr-deref Write in io_uring_cancel_sqpoll ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:101 [inline] BUG: KASAN: null-ptr-deref in atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] BUG: KASAN: null-ptr-deref in io_uring_cancel_sqpoll+0x150/0x310 fs/io_uring.c:8930 Write of size 4 at addr 0000000000000114 by task iou-sqp-31588/31596 CPU: 0 PID: 31596 Comm: iou-sqp-31588 Not tainted 5.12.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 __kasan_report mm/kasan/report.c:403 [inline] kasan_report.cold+0x5f/0xd8 mm/kasan/report.c:416 check_region_inline mm/kasan/generic.c:180 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:186 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] io_uring_cancel_sqpoll+0x150/0x310 fs/io_uring.c:8930 io_sq_thread+0x47e/0x1310 fs/io_uring.c:6873 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 ================================================================== Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 31596 Comm: iou-sqp-31588 Tainted: G B 5.12.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 panic+0x306/0x73d kernel/panic.c:231 end_report mm/kasan/report.c:102 [inline] end_report.cold+0x5a/0x5a mm/kasan/report.c:88 __kasan_report mm/kasan/report.c:406 [inline] kasan_report.cold+0x6a/0xd8 mm/kasan/report.c:416 check_region_inline mm/kasan/generic.c:180 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:186 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_inc include/asm-generic/atomic-instrumented.h:240 [inline] io_uring_cancel_sqpoll+0x150/0x310 fs/io_uring.c:8930 io_sq_thread+0x47e/0x1310 fs/io_uring.c:6873 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Kernel Offset: disabled Rebooting in 86400 seconds.. Tested on: commit: 734551df io_uring: fix shared sqpoll cancellation hangs git tree: git://git.kernel.dk/linux-block for-5.13/io_uring console output: https://syzkaller.appspot.com/x/log.txt?x=175fec6dd00000 kernel config: https://syzkaller.appspot.com/x/.config?x=601d16d8cd22e315 dashboard link: https://syzkaller.appspot.com/bug?extid=47fc00967b06a3019bd2 compiler:
