================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] BUG: KASAN: null-ptr-deref in buffer_busy fs/buffer.c:2882 [inline] BUG: KASAN: null-ptr-deref in drop_buffers+0x74/0x4b4 fs/buffer.c:2894 Read of size 4 at addr 0000000000000060 by task syz-executor.0/25387 CPU: 1 PID: 25387 Comm: syz-executor.0 Tainted: G B 6.8.0-rc5-syzkaller-g9abbc24128bc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:291 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:298 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd0/0x124 lib/dump_stack.c:106 print_report+0xe4/0x518 mm/kasan/report.c:491 kasan_report+0xd8/0x138 mm/kasan/report.c:601 kasan_check_range+0x254/0x294 mm/kasan/generic.c:189 __kasan_check_read+0x20/0x30 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:68 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] buffer_busy fs/buffer.c:2882 [inline] drop_buffers+0x74/0x4b4 fs/buffer.c:2894 try_to_free_buffers+0x1e0/0x308 fs/buffer.c:2924 filemap_release_folio+0x1ec/0x248 mm/filemap.c:4089 shrink_folio_list+0x1bb4/0x4b84 mm/vmscan.c:1369 shrink_inactive_list mm/vmscan.c:1914 [inline] shrink_list mm/vmscan.c:2155 [inline] shrink_lruvec+0x12a4/0x27b4 mm/vmscan.c:5681 shrink_node_memcgs mm/vmscan.c:5867 [inline] shrink_node+0xe10/0x2268 mm/vmscan.c:5902 shrink_zones mm/vmscan.c:6141 [inline] do_try_to_free_pages+0x5f8/0x14fc mm/vmscan.c:6203 try_to_free_mem_cgroup_pages+0x3a0/0xbac mm/vmscan.c:6518 try_charge_memcg+0x4a4/0x148c mm/memcontrol.c:2782 try_charge mm/memcontrol.c:2930 [inline] charge_memcg mm/memcontrol.c:7276 [inline] __mem_cgroup_charge+0xa8/0x148 mm/memcontrol.c:7291 mem_cgroup_charge include/linux/memcontrol.h:690 [inline] shmem_alloc_and_add_folio+0x330/0xce0 mm/shmem.c:1677 shmem_get_folio_gfp+0x6d0/0x1670 mm/shmem.c:2052 shmem_read_folio_gfp+0x100/0x194 mm/shmem.c:4914 drm_gem_get_pages+0x1c0/0x880 drivers/gpu/drm/drm_gem.c:568 drm_gem_shmem_get_pages drivers/gpu/drm/drm_gem_shmem_helper.c:178 [inline] drm_gem_shmem_mmap+0x1ec/0x670 drivers/gpu/drm/drm_gem_shmem_helper.c:614 drm_gem_shmem_object_mmap+0x28/0x38 include/drm/drm_gem_shmem_helper.h:260 drm_gem_mmap_obj+0x18c/0x568 drivers/gpu/drm/drm_gem.c:1061 drm_gem_mmap+0x400/0x6a0 drivers/gpu/drm/drm_gem.c:1139 call_mmap include/linux/fs.h:2090 [inline] mmap_region+0xc50/0x1a28 mm/mmap.c:2824 do_mmap+0x9f4/0xff4 mm/mmap.c:1382 vm_mmap_pgoff+0x1a0/0x3d4 mm/util.c:556 ksys_mmap_pgoff+0x3c8/0x5b0 mm/mmap.c:1428 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline] __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline] __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 ================================================================== Unable to handle kernel paging request at virtual address dfff80000000000c KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067] Mem abort info: ESR = 0x0000000096000005 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x05: level 1 translation fault Data abort info: ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [dfff80000000000c] address between user and kernel address ranges Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP Modules linked in: CPU: 1 PID: 25387 Comm: syz-executor.0 Tainted: G B 6.8.0-rc5-syzkaller-g9abbc24128bc #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] pc : atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] pc : buffer_busy fs/buffer.c:2882 [inline] pc : drop_buffers+0x80/0x4b4 fs/buffer.c:2894 lr : instrument_atomic_read include/linux/instrumented.h:68 [inline] lr : atomic_read include/linux/atomic/atomic-instrumented.h:32 [inline] lr : buffer_busy fs/buffer.c:2882 [inline] lr : drop_buffers+0x74/0x4b4 fs/buffer.c:2894 sp : ffff8000999a6050 x29: ffff8000999a6080 x28: 1fffffbff86b3078 x27: ffff000113c25b58 x26: dfff800000000000 x25: 1ffff00013334c1c x24: dfff800000000000 x23: 0000000000000000 x22: fffffdffc35983c8 x21: 0000000000000000 x20: 0000000000000060 x19: 0000000000000000 x18: 1fffe00036804796 x17: ffff80008ec8d000 x16: ffff80008ad5a610 x15: 0000000000000001 x14: 1ffff000123e1a9c x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000040000 x10: 000000000003ffff x9 : 0000000000000003 x8 : 000000000000000c x7 : 1fffe00036804797 x6 : ffff800080297af0 x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff8000801c0904 x2 : 0000000000000001 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] buffer_busy fs/buffer.c:2882 [inline] drop_buffers+0x80/0x4b4 fs/buffer.c:2894 try_to_free_buffers+0x1e0/0x308 fs/buffer.c:2924 filemap_release_folio+0x1ec/0x248 mm/filemap.c:4089 shrink_folio_list+0x1bb4/0x4b84 mm/vmscan.c:1369 shrink_inactive_list mm/vmscan.c:1914 [inline] shrink_list mm/vmscan.c:2155 [inline] shrink_lruvec+0x12a4/0x27b4 mm/vmscan.c:5681 shrink_node_memcgs mm/vmscan.c:5867 [inline] shrink_node+0xe10/0x2268 mm/vmscan.c:5902 shrink_zones mm/vmscan.c:6141 [inline] do_try_to_free_pages+0x5f8/0x14fc mm/vmscan.c:6203 try_to_free_mem_cgroup_pages+0x3a0/0xbac mm/vmscan.c:6518 try_charge_memcg+0x4a4/0x148c mm/memcontrol.c:2782 try_charge mm/memcontrol.c:2930 [inline] charge_memcg mm/memcontrol.c:7276 [inline] __mem_cgroup_charge+0xa8/0x148 mm/memcontrol.c:7291 mem_cgroup_charge include/linux/memcontrol.h:690 [inline] shmem_alloc_and_add_folio+0x330/0xce0 mm/shmem.c:1677 shmem_get_folio_gfp+0x6d0/0x1670 mm/shmem.c:2052 shmem_read_folio_gfp+0x100/0x194 mm/shmem.c:4914 drm_gem_get_pages+0x1c0/0x880 drivers/gpu/drm/drm_gem.c:568 drm_gem_shmem_get_pages drivers/gpu/drm/drm_gem_shmem_helper.c:178 [inline] drm_gem_shmem_mmap+0x1ec/0x670 drivers/gpu/drm/drm_gem_shmem_helper.c:614 drm_gem_shmem_object_mmap+0x28/0x38 include/drm/drm_gem_shmem_helper.h:260 drm_gem_mmap_obj+0x18c/0x568 drivers/gpu/drm/drm_gem.c:1061 drm_gem_mmap+0x400/0x6a0 drivers/gpu/drm/drm_gem.c:1139 call_mmap include/linux/fs.h:2090 [inline] mmap_region+0xc50/0x1a28 mm/mmap.c:2824 do_mmap+0x9f4/0xff4 mm/mmap.c:1382 vm_mmap_pgoff+0x1a0/0x3d4 mm/util.c:556 ksys_mmap_pgoff+0x3c8/0x5b0 mm/mmap.c:1428 __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline] __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline] __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 Code: 97f86821 d343fe88 12000a89 11000d29 (38fa6908) ---[ end trace 0000000000000000 ]--- ---------------- Code disassembly (best guess): 0: 97f86821 bl 0xffffffffffe1a084 4: d343fe88 lsr x8, x20, #3 8: 12000a89 and w9, w20, #0x7 c: 11000d29 add w9, w9, #0x3 * 10: 38fa6908 ldrsb w8, [x8, x26] <-- trapping instruction