Hello, The following program triggers kmalloc size WARNING in vc_do_resize:
// autogenerated by syzkaller (http://github.com/google/syzkaller) #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <termios.h> #include <sys/ioctl.h> int main() { int fd = open("/dev/tty1", O_RDWR); struct winsize ws; ws.ws_row = 0x1000; ws.ws_col = 0x5dc; ws.ws_xpixel = 0x2; ws.ws_ypixel = 0x0; ioctl(fd, TIOCSWINSZ, &ws); return 0; } ------------[ cut here ]------------ WARNING: CPU: 3 PID: 7642 at mm/page_alloc.c:2999 __alloc_pages_nodemask+0x7d2/0x1760() Modules linked in: CPU: 3 PID: 7642 Comm: a.out Not tainted 4.4.0+ #276 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 00000000ffffffff ffff88006d24f610 ffffffff82999e2d 0000000000000000 ffff880060d9af80 ffffffff86475560 ffff88006d24f650 ffffffff81352089 ffffffff816721e2 ffffffff86475560 0000000000000bb7 00000000024240c0 Call Trace: [< inline >] __dump_stack lib/dump_stack.c:15 [<ffffffff82999e2d>] dump_stack+0x6f/0xa2 lib/dump_stack.c:50 [<ffffffff81352089>] warn_slowpath_common+0xd9/0x140 kernel/panic.c:482 [<ffffffff813522b9>] warn_slowpath_null+0x29/0x30 kernel/panic.c:515 [< inline >] __alloc_pages_slowpath mm/page_alloc.c:2999 [<ffffffff816721e2>] __alloc_pages_nodemask+0x7d2/0x1760 mm/page_alloc.c:3253 [<ffffffff8174a799>] alloc_pages_current+0xe9/0x450 mm/mempolicy.c:2090 [< inline >] alloc_pages include/linux/gfp.h:459 [<ffffffff8166df66>] alloc_kmem_pages+0x16/0x100 mm/page_alloc.c:3433 [<ffffffff816c698f>] kmalloc_order+0x1f/0x80 mm/slab_common.c:1008 [<ffffffff816c6a0f>] kmalloc_order_trace+0x1f/0x140 mm/slab_common.c:1019 [< inline >] kmalloc_large include/linux/slab.h:395 [<ffffffff8175b624>] __kmalloc+0x2f4/0x340 mm/slub.c:3557 [< inline >] kmalloc include/linux/slab.h:468 [<ffffffff82d47800>] vc_do_resize+0x2c0/0x1140 drivers/tty/vt/vt.c:874 [<ffffffff82d4878a>] vt_resize+0xaa/0xe0 drivers/tty/vt/vt.c:993 [< inline >] tiocswinsz drivers/tty/tty_io.c:2357 [<ffffffff82cf22b3>] tty_ioctl+0x1083/0x2160 drivers/tty/tty_io.c:2869 [< inline >] vfs_ioctl fs/ioctl.c:43 [<ffffffff817efdac>] do_vfs_ioctl+0x18c/0xfb0 fs/ioctl.c:674 [< inline >] SYSC_ioctl fs/ioctl.c:689 [<ffffffff817f0c5f>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:680 [<ffffffff86336c36>] entry_SYSCALL_64_fastpath+0x16/0x7a arch/x86/entry/entry_64.S:185 ---[ end trace cc28f7cc9d447282 ]--- I think that either the kmalloc should use __GFP_NOWARN or vc_do_resize should do stricter size check. On commit 30f05309bde49295e02e45c7e615f73aa4e0ccc2.
