/* RomFS storage access routines * * Copyright © 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include "internal.h" #if !defined(CONFIG_ROMFS_ON_MTD) && !defined(CONFIG_ROMFS_ON_BLOCK) #error no ROMFS backing store interface configured #endif #ifdef CONFIG_ROMFS_ON_MTD #define ROMFS_MTD_READ(sb, ...) mtd_read((sb)->s_mtd, ##__VA_ARGS__) /* * read data from an romfs image on an MTD device */ static int romfs_mtd_read(struct super_block *sb, unsigned long pos, void *buf, size_t buflen) { size_t rlen; int ret; ret = ROMFS_MTD_READ(sb, pos, buflen, &rlen, buf); return (ret < 0 || rlen != buflen) ? -EIO : 0; } /* * determine the length of a string in a romfs image on an MTD device */ static ssize_t romfs_mtd_strnlen(struct super_block *sb, unsigned long pos, size_t maxlen) { ssize_t n = 0; size_t segment; u_char buf[16], *p; size_t len; int ret; /* scan the string up to 16 bytes at a time */ while (maxlen > 0) { segment = min_t(size_t, maxlen, 16); ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf); if (ret < 0) return ret; p = memchr(buf, 0, len); if (p) return n + (p - buf); maxlen -= len; pos += len; n += len; } return n; } /* * compare a string to one in a romfs image on MTD * - return 1 if matched, 0 if differ, -ve if error */ static int romfs_mtd_strcmp(struct super_block *sb, unsigned long pos, const char *str, size_t size) { u_char buf[17]; size_t len, segment; int ret; /* scan the string up to 16 bytes at a time, and attempt to grab the * trailing NUL whilst we're at it */ buf[0] = 0xff; while (size > 0) { segment = min_t(size_t, size + 1, 17); ret = ROMFS_MTD_READ(sb, pos, segment, &len, buf); if (ret < 0) return ret; len--; if (memcmp(buf, str, len) != 0) return 0; buf[0] = buf[len]; size -= len; pos += len; str += len; } /* check the trailing NUL was */ if (buf[0]) return 0; return 1; } #endif /* CONFIG_ROMFS_ON_MTD */ #ifdef CONFIG_ROMFS_ON_BLOCK /* * read data from an romfs image on a block device */ static int romfs_blk_read(struct super_block *sb, unsigned long pos, void *buf, size_t buflen) { struct buffer_head *bh; unsigned long offset; size_t segment; /* copy the string up to blocksize bytes at a time */ while (buflen > 0) { offset = pos & (ROMBSIZE - 1); segment = min_t(size_t, buflen, ROMBSIZE - offset); bh = sb_bread(sb, pos >> ROMBSBITS); if (!bh) return -EIO; memcpy(buf, bh->b_data + offset, segment); brelse(bh); buf += segment; buflen -= segment; pos += segment; } return 0; } /* * determine the length of a string in romfs on a block device */ static ssize_t romfs_blk_strnlen(struct super_block *sb, unsigned long pos, size_t limit) { struct buffer_head *bh; unsigned long offset; ssize_t n = 0; size_t segment; u_char *buf, *p; /* scan the string up to blocksize bytes at a time */ while (limit > 0) { offset = pos & (ROMBSIZE - 1); segment = min_t(size_t, limit, ROMBSIZE - offset); bh = sb_bread(sb, pos >> ROMBSBITS); if (!bh) return -EIO; buf = bh->b_data + offset; p = memchr(buf, 0, segment); brelse(bh); if (p) return n + (p - buf); limit -= segment; pos += segment; n += segment; } return n; } /* * compare a string to one in a romfs image on a block device * - return 1 if matched, 0 if differ, -ve if error */ static int romfs_blk_strcmp(struct super_block *sb, unsigned long pos, const char *str, size_t size) { struct buffer_head *bh; unsigned long offset; size_t segment; bool matched, terminated = false; /* compare string up to a block at a time */ while (size > 0) { offset = pos & (ROMBSIZE - 1); segment = min_t(size_t, size, ROMBSIZE - offset); bh = sb_bread(sb, pos >> ROMBSBITS); if (!bh) return -EIO; matched = (memcmp(bh->b_data + offset, str, segment) == 0); size -= segment; pos += segment; str += segment; if (matched && size == 0 && offset + segment < ROMBSIZE) { if (!bh->b_data[offset + segment]) terminated = true; else matched = false; } brelse(bh); if (!matched) return 0; } if (!terminated) { /* the terminating NUL must be on the first byte of the next * block */ BUG_ON((pos & (ROMBSIZE - 1)) != 0); bh = sb_bread(sb, pos >> ROMBSBITS); if (!bh) return -EIO; matched = !bh->b_data[0]; brelse(bh); if (!matched) return 0; } return 1; } #endif /* CONFIG_ROMFS_ON_BLOCK */ /* * read data from the romfs image */ int romfs_dev_read(struct super_block *sb, unsigned long pos, void *buf, size_t buflen) { size_t limit; limit = romfs_maxsize(sb); if (pos >= limit) return -EIO; if (buflen > limit - pos) buflen = limit - pos; #ifdef CONFIG_ROMFS_ON_MTD if (sb->s_mtd) return romfs_mtd_read(sb, pos, buf, buflen); #endif #ifdef CONFIG_ROMFS_ON_BLOCK if (sb->s_bdev) return romfs_blk_read(sb, pos, buf, buflen); #endif return -EIO; } /* * determine the length of a string in romfs */ ssize_t romfs_dev_strnlen(struct super_block *sb, unsigned long pos, size_t maxlen) { size_t limit; limit = romfs_maxsize(sb); if (pos >= limit) return -EIO; if (maxlen > limit - pos) maxlen = limit - pos; #ifdef CONFIG_ROMFS_ON_MTD if (sb->s_mtd) return romfs_mtd_strnlen(sb, pos, maxlen); #endif #ifdef CONFIG_ROMFS_ON_BLOCK if (sb->s_bdev) return romfs_blk_strnlen(sb, pos, maxlen); #endif return -EIO; } /* * compare a string to one in romfs * - the string to be compared to, str, may not be NUL-terminated; instead the * string is of the specified size * - return 1 if matched, 0 if differ, -ve if error */ int romfs_dev_strcmp(struct super_block *sb, unsigned long pos, const char *str, size_t size) { size_t limit; limit = romfs_maxsize(sb); if (pos >= limit) return -EIO; if (size > ROMFS_MAXFN) return -ENAMETOOLONG; if (size + 1 > limit - pos) return -EIO; #ifdef CONFIG_ROMFS_ON_MTD if (sb->s_mtd) return romfs_mtd_strcmp(sb, pos, str, size); #endif #ifdef CONFIG_ROMFS_ON_BLOCK if (sb->s_bdev) return romfs_blk_strcmp(sb, pos, str, size); #endif return -EIO; } 5] drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper] intel_atomic_commit_tail+0x749/0xfe0 [i915] intel_atomic_commit+0x3cb/0x4f0 [i915] drm_atomic_commit+0x4b/0x50 [drm] restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper] drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper] drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper] intel_fbdev_set_par+0x18/0x70 [i915] fb_set_var+0x236/0x460 fbcon_blank+0x30f/0x350 do_unblank_screen+0xd2/0x1a0 vt_ioctl+0x507/0x12a0 tty_ioctl+0x355/0xc30 do_vfs_ioctl+0xa3/0x5e0 SyS_ioctl+0x79/0x90 entry_SYSCALL_64_fastpath+0x13/0x94 - i915 unpin_work workqueue: intel_unpin_work_fn+0x58/0x140 [i915] process_one_work+0x1f1/0x480 worker_thread+0x48/0x4d0 kthread+0x101/0x140 and this patch purely papers over the issue by adding a NULL pointer check and a WARN_ON_ONCE() to avoid the oops that would then generally make the machine unresponsive. Other callers of i915_gem_object_to_ggtt() seem to also check for the returned pointer being NULL and warn about it, so this clearly has happened before in other places. [ Reported it originally to the i915 developers on Jan 8, applying the ugly workaround on my own now after triggering the problem for the second time with no feedback. This is likely to be the same bug reported as https://bugs.freedesktop.org/show_bug.cgi?id=98829 https://bugs.freedesktop.org/show_bug.cgi?id=99134 which has a patch for the underlying problem, but it hasn't gotten to me, so I'm applying the workaround. ] Cc: Daniel Vetter <daniel.vetter@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Imre Deak <imre.deak@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'net/sched/sch_generic.c')