Revision f6b57101a6b31277a4bde1d8028c46e898bd2ff2 authored by Dom Cobley on 21 January 2021, 10:57:59 UTC, committed by Maxime Ripard on 25 January 2021, 10:53:44 UTC
Fixes failure with 4096x1080 resolutions

[  284.315379] WARNING: CPU: 1 PID: 901 at drivers/gpu/drm/vc4/vc4_plane.c:981 vc4_plane_mode_set+0x1374/0x13c4
[  284.315385] Modules linked in: ir_rc5_decoder rpivid_hevc(C) bcm2835_codec(C) bcm2835_isp(C) bcm2835_mmal_vchiq(C) bcm2835_gpiomem v4l2_mem2mem videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_common videodev mc cdc_acm xpad ir_rc6_decoder rc_rc6_mce gpio_ir_recv fuse
[  284.315509] CPU: 1 PID: 901 Comm: kodi.bin Tainted: G         C        5.10.7 #1
[  284.315514] Hardware name: BCM2711
[  284.315518] Backtrace:
[  284.315533] [<c0cc5ca0>] (dump_backtrace) from [<c0cc6014>] (show_stack+0x20/0x24)
[  284.315540]  r7:ffffffff r6:00000000 r5:68000013 r4:c18ecf1c
[  284.315549] [<c0cc5ff4>] (show_stack) from [<c0cca638>] (dump_stack+0xc4/0xf0)
[  284.315558] [<c0cca574>] (dump_stack) from [<c022314c>] (__warn+0xfc/0x158)
[  284.315564]  r9:00000000 r8:00000009 r7:000003d5 r6:00000009 r5:c08cc7dc r4:c0fd09b8
[  284.315572] [<c0223050>] (__warn) from [<c0cc67ec>] (warn_slowpath_fmt+0x74/0xe4)
[  284.315577]  r7:c08cc7dc r6:000003d5 r5:c0fd09b8 r4:00000000
[  284.315584] [<c0cc677c>] (warn_slowpath_fmt) from [<c08cc7dc>] (vc4_plane_mode_set+0x1374/0x13c4)
[  284.315589]  r8:00000000 r7:00000000 r6:00001000 r5:c404c600 r4:c2e34600
[  284.315596] [<c08cb468>] (vc4_plane_mode_set) from [<c08cc984>] (vc4_plane_atomic_check+0x40/0x1c0)
[  284.315601]  r10:00000001 r9:c2e34600 r8:c0e67068 r7:c0fc44e0 r6:c2ce3640 r5:c3d636c0
[  284.315605]  r4:c2e34600
[  284.315614] [<c08cc944>] (vc4_plane_atomic_check) from [<c0860504>] (drm_atomic_helper_check_planes+0xec/0x1ec)
[  284.315620]  r9:c2e34600 r8:c0e67068 r7:c0fc44e0 r6:c2ce3640 r5:c3d636c0 r4:00000006
[  284.315627] [<c0860418>] (drm_atomic_helper_check_planes) from [<c0860658>] (drm_atomic_helper_check+0x54/0x9c)
[  284.315633]  r9:c2e35400 r8:00000006 r7:00000000 r6:c2ba7800 r5:c3d636c0 r4:00000000
[  284.315641] [<c0860604>] (drm_atomic_helper_check) from [<c08b7ca8>] (vc4_atomic_check+0x25c/0x454)
[  284.315645]  r7:00000000 r6:c2ba7800 r5:00000001 r4:c3d636c0
[  284.315652] [<c08b7a4c>] (vc4_atomic_check) from [<c0881278>] (drm_atomic_check_only+0x5cc/0x7e0)
[  284.315658]  r10:c404c6c8 r9:ffffffff r8:c472c480 r7:00000003 r6:c3d636c0 r5:00000000
[  284.315662]  r4:0000003c r3:c08b7a4c
[  284.315670] [<c0880cac>] (drm_atomic_check_only) from [<c089ba60>] (drm_mode_atomic_ioctl+0x758/0xa7c)
[  284.315675]  r10:c3d46000 r9:c3d636c0 r8:c2ce8a70 r7:027e3a54 r6:00000043 r5:c1fbb800
[  284.315679]  r4:0281a858
[  284.315688] [<c089b308>] (drm_mode_atomic_ioctl) from [<c086e9f8>] (drm_ioctl_kernel+0xc4/0x108)
[  284.315693]  r10:c03864bc r9:c1fbb800 r8:c3d47e64 r7:c089b308 r6:00000002 r5:c2ba7800
[  284.315697]  r4:00000000
[  284.315705] [<c086e934>] (drm_ioctl_kernel) from [<c086ee28>] (drm_ioctl+0x1e8/0x3a0)
[  284.315711]  r9:c1fbb800 r8:000000bc r7:c3d47e64 r6:00000038 r5:c0e59570 r4:00000038
[  284.315719] [<c086ec40>] (drm_ioctl) from [<c041f354>] (sys_ioctl+0x35c/0x914)
[  284.315724]  r10:c2d08200 r9:00000000 r8:c36fa300 r7:befdd870 r6:c03864bc r5:c36fa301
[  284.315728]  r4:c03864bc
[  284.315735] [<c041eff8>] (sys_ioctl) from [<c0200040>] (ret_fast_syscall+0x0/0x28)
[  284.315739] Exception stack(0xc3d47fa8 to 0xc3d47ff0)
[  284.315745] 7fa0:                   027eb750 befdd870 00000000 c03864bc befdd870 00000000
[  284.315750] 7fc0: 027eb750 befdd870 c03864bc 00000036 027e3948 0281a640 0281a850 027e3a50
[  284.315756] 7fe0: b4b64100 befdd844 b4b5ba2c b49c994c
[  284.315762]  r10:00000036 r9:c3d46000 r8:c0200204 r7:00000036 r6:c03864bc r5:befdd870
[  284.315765]  r4:027eb750

Fixes: c54619b0bfb3 ("drm/vc4: Add support for the BCM2711 HVS5")
Signed-off-by: Dom Cobley <popcornmix@gmail.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Tested-By: Lucas Nussbaum <lucas@debian.org>
Tested-By: Ryutaroh Matsumoto <ryutaroh@ict.e.titech.ac.jp>
Link: https://patchwork.freedesktop.org/patch/msgid/20210121105759.1262699-2-maxime@cerno.tech
1 parent 78e5330
Raw File
strnlen_user.c
// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
#include <linux/bitops.h>

#include <asm/word-at-a-time.h>

/*
 * Do a strnlen, return length of string *with* final '\0'.
 * 'count' is the user-supplied count, while 'max' is the
 * address space maximum.
 *
 * Return 0 for exceptions (which includes hitting the address
 * space maximum), or 'count+1' if hitting the user-supplied
 * maximum count.
 *
 * NOTE! We can sometimes overshoot the user-supplied maximum
 * if it fits in a aligned 'long'. The caller needs to check
 * the return value against "> max".
 */
static inline long do_strnlen_user(const char __user *src, unsigned long count, unsigned long max)
{
	const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS;
	unsigned long align, res = 0;
	unsigned long c;

	/*
	 * Do everything aligned. But that means that we
	 * need to also expand the maximum..
	 */
	align = (sizeof(unsigned long) - 1) & (unsigned long)src;
	src -= align;
	max += align;

	unsafe_get_user(c, (unsigned long __user *)src, efault);
	c |= aligned_byte_mask(align);

	for (;;) {
		unsigned long data;
		if (has_zero(c, &data, &constants)) {
			data = prep_zero_mask(c, data, &constants);
			data = create_zero_mask(data);
			return res + find_zero(data) + 1 - align;
		}
		res += sizeof(unsigned long);
		/* We already handled 'unsigned long' bytes. Did we do it all ? */
		if (unlikely(max <= sizeof(unsigned long)))
			break;
		max -= sizeof(unsigned long);
		unsafe_get_user(c, (unsigned long __user *)(src+res), efault);
	}
	res -= align;

	/*
	 * Uhhuh. We hit 'max'. But was that the user-specified maximum
	 * too? If so, return the marker for "too long".
	 */
	if (res >= count)
		return count+1;

	/*
	 * Nope: we hit the address space limit, and we still had more
	 * characters the caller would have wanted. That's 0.
	 */
efault:
	return 0;
}

/**
 * strnlen_user: - Get the size of a user string INCLUDING final NUL.
 * @str: The string to measure.
 * @count: Maximum count (including NUL character)
 *
 * Context: User context only. This function may sleep if pagefaults are
 *          enabled.
 *
 * Get the size of a NUL-terminated string in user space.
 *
 * Returns the size of the string INCLUDING the terminating NUL.
 * If the string is too long, returns a number larger than @count. User
 * has to check the return value against "> count".
 * On exception (or invalid count), returns 0.
 *
 * NOTE! You should basically never use this function. There is
 * almost never any valid case for using the length of a user space
 * string, since the string can be changed at any time by other
 * threads. Use "strncpy_from_user()" instead to get a stable copy
 * of the string.
 */
long strnlen_user(const char __user *str, long count)
{
	unsigned long max_addr, src_addr;

	if (unlikely(count <= 0))
		return 0;

	max_addr = user_addr_max();
	src_addr = (unsigned long)untagged_addr(str);
	if (likely(src_addr < max_addr)) {
		unsigned long max = max_addr - src_addr;
		long retval;

		/*
		 * Truncate 'max' to the user-specified limit, so that
		 * we only have one limit we need to check in the loop
		 */
		if (max > count)
			max = count;

		if (user_read_access_begin(str, max)) {
			retval = do_strnlen_user(str, count, max);
			user_read_access_end();
			return retval;
		}
	}
	return 0;
}
EXPORT_SYMBOL(strnlen_user);
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