Subject: [syzbot] [mm?] kernel BUG in do_page_mkwrite

From: syzbot <[email-masked]>
Date: Wed, 16 Aug 2023 09:56:55 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    2ccdd1b13c59 Linux 6.5-rc6
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=143b6d3ba80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8fc59e2140295873
dashboard link: https://syzkaller.appspot.com/bug?extid=cfba1abcb2cf7b39a320
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=1032446ba80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16576b4fa80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e6e598627dd6/disk-2ccdd1b1.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/486c6739d779/vmlinux-2ccdd1b1.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5da0f3ac1d56/bzImage-2ccdd1b1.xz

The issue was bisected to:

commit a5b44c4adb1699661d22e5152fb26885f30a2e4c
Author: Thomas Zimmermann <[email-masked]>
Date:   Mon Mar 20 15:07:44 2023 +0000

    drm/fbdev-generic: Always use shadow buffering

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11349b73a80000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=13349b73a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=15349b73a80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]
Fixes: a5b44c4adb16 ("drm/fbdev-generic: Always use shadow buffering")

 vm_area_alloc_pages mm/vmalloc.c:3059 [inline]
 __vmalloc_area_node mm/vmalloc.c:3135 [inline]
 __vmalloc_node_range+0xa6e/0x1540 mm/vmalloc.c:3316
 __vmalloc_node mm/vmalloc.c:3381 [inline]
 vzalloc+0x6b/0x80 mm/vmalloc.c:3454
 drm_fbdev_generic_helper_fb_probe+0x300/0x6d0 drivers/gpu/drm/drm_fbdev_generic.c:97
 drm_fb_helper_single_fb_probe drivers/gpu/drm/drm_fb_helper.c:1668 [inline]
 __drm_fb_helper_initial_config_and_unlock+0xc31/0x1600 drivers/gpu/drm/drm_fb_helper.c:1846
 drm_fb_helper_initial_config drivers/gpu/drm/drm_fb_helper.c:1936 [inline]
 drm_fb_helper_initial_config+0x44/0x60 drivers/gpu/drm/drm_fb_helper.c:1928
 drm_fbdev_generic_client_hotplug+0x1a7/0x270 drivers/gpu/drm/drm_fbdev_generic.c:280
 drm_client_register+0x195/0x280 drivers/gpu/drm/drm_client.c:149
 drm_fbdev_generic_setup+0x11c/0x330 drivers/gpu/drm/drm_fbdev_generic.c:342
 vkms_create drivers/gpu/drm/vkms/vkms_drv.c:208 [inline]
 vkms_init+0x625/0x760 drivers/gpu/drm/vkms/vkms_drv.c:234
 do_one_initcall+0x117/0x630 init/main.c:1232
 do_initcall_level init/main.c:1294 [inline]
 do_initcalls init/main.c:1310 [inline]
 do_basic_setup init/main.c:1329 [inline]
 kernel_init_freeable+0x5bd/0x8f0 init/main.c:1546
page_owner free stack trace missing
------------[ cut here ]------------
kernel BUG at mm/memory.c:2955!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 5026 Comm: syz-executor380 Not tainted 6.5.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:do_page_mkwrite+0x468/0x680 mm/memory.c:2955
Code: de e8 cc 15 c2 ff 84 db 0f 85 c1 00 00 00 48 89 eb e9 76 fe ff ff e8 87 1a c2 ff 48 c7 c6 a0 b3 78 8a 48 89 ef e8 78 3d fe ff <0f> 0b 41 bc 02 00 00 00 e9 99 fe ff ff e8 66 1a c2 ff be d0 03 00
RSP: 0018:ffffc900030efba8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888079cec200 RSI: ffffffff81c30648 RDI: ffffffff8ac7eec0
RBP: ffffea0005007780 R08: 0000000000000000 R09: fffffbfff1d55d7a
R10: ffffffff8eaaebd7 R11: 0000000000000001 R12: 0000000000000200
R13: ffffea0005007780 R14: 0000000000000a55 R15: 0000000000000000
FS:  0000555557128380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb85a07fe08 CR3: 0000000023b67000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 wp_page_shared mm/memory.c:3294 [inline]
 do_wp_page+0x3a0/0x3710 mm/memory.c:3376
 handle_pte_fault mm/memory.c:4955 [inline]
 __handle_mm_fault+0x1af7/0x3b80 mm/memory.c:5079
 handle_mm_fault+0x2ab/0x9d0 mm/memory.c:5233
 do_user_addr_fault+0x446/0xfc0 arch/x86/mm/fault.c:1392
 handle_page_fault arch/x86/mm/fault.c:1486 [inline]
 exc_page_fault+0x5c/0xd0 arch/x86/mm/fault.c:1542
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570
RIP: 0033:0x7fb859ff27a0
Code: 00 41 b8 11 80 02 00 b9 06 00 00 01 ba 00 60 b3 00 be 00 00 00 20 bf 09 00 00 00 31 c0 48 c7 04 24 00 c0 2f 00 e8 30 fc 02 00 <c6> 04 25 08 00 00 20 00 45 31 c0 48 b8 2f 64 65 76 2f 66 62 30 b9
RSP: 002b:00007ffeec409b10 EFLAGS: 00010217
RAX: 0000000020000000 RBX: 00007ffeec409ce8 RCX: 00007fb85a0223e9
RDX: 0000000001000006 RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007fb85a095610 R08: 0000000000000004 R09: 00000000002fc000
R10: 0000000000028011 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffeec409cd8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:do_page_mkwrite+0x468/0x680 mm/memory.c:2955
Code: de e8 cc 15 c2 ff 84 db 0f 85 c1 00 00 00 48 89 eb e9 76 fe ff ff e8 87 1a c2 ff 48 c7 c6 a0 b3 78 8a 48 89 ef e8 78 3d fe ff <0f> 0b 41 bc 02 00 00 00 e9 99 fe ff ff e8 66 1a c2 ff be d0 03 00
RSP: 0018:ffffc900030efba8 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff888079cec200 RSI: ffffffff81c30648 RDI: ffffffff8ac7eec0
RBP: ffffea0005007780 R08: 0000000000000000 R09: fffffbfff1d55d7a
R10: ffffffff8eaaebd7 R11: 0000000000000001 R12: 0000000000000200
R13: ffffea0005007780 R14: 0000000000000a55 R15: 0000000000000000
FS:  0000555557128380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb85a07fe08 CR3: 0000000023b67000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

---
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