#include #include #include #include #include #include #include #include #include #include static int verbose; static void do_read(int fd, int len) { unsigned char buf[32], *bp; int status; /* read at least 2 bytes, no more than 32 */ if (len < 2) len = 2; else if (len > sizeof(buf)) len = sizeof(buf); memset(buf, 0, sizeof buf); status = read(fd, buf, len); if (status < 0) { perror("read"); return; } if (status != len) { fprintf(stderr, "short read\n"); return; } printf("read(%2d, %2d): %02x %02x,", len, status, buf[0], buf[1]); status -= 2; bp = buf + 2; while (status-- > 0) printf(" %02x", *bp++); printf("\n"); } static void do_msg(int fd, int len) { struct spi_ioc_transfer xfer[2]; unsigned char buf[32], *bp; int status; memset(xfer, 0, sizeof xfer); memset(buf, 0, sizeof buf); if (len > sizeof buf) len = sizeof buf; buf[0] = 0xaa; xfer[0].tx_buf = (unsigned long)buf; xfer[0].len = 1; xfer[1].rx_buf = (unsigned long) buf; xfer[1].len = len; status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer); if (status < 0) { perror("SPI_IOC_MESSAGE"); return; } printf("response(%2d, %2d): ", len, status); for (bp = buf; len; len--) printf(" %02x", *bp++); printf("\n"); } static void dumpstat(const char *name, int fd) { __u8 lsb, bits; __u32 mode, speed; if (ioctl(fd, SPI_IOC_RD_MODE32, &mode) < 0) { perror("SPI rd_mode"); return; } if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) { perror("SPI rd_lsb_fist"); return; } if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) { perror("SPI bits_per_word"); return; } if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) { perror("SPI max_speed_hz"); return; } printf("%s: spi mode 0x%x, %d bits %sper word, %d Hz max\n", name, mode, bits, lsb ? "(lsb first) " : "", speed); } int main(int argc, char **argv) { int c; int readcount = 0; int msglen = 0; int fd; const char *name; while ((c = getopt(argc, argv, "hm:r:v")) != EOF) { switch (c) { case 'm': msglen = atoi(optarg); if (msglen < 0) goto usage; continue; case 'r': readcount = atoi(optarg); if (readcount < 0) goto usage; continue; case 'v': verbose++; continue; case 'h': case '?': usage: fprintf(stderr, "usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n", argv[0]); return 1; } } if ((optind + 1) != argc) goto usage; name = argv[optind]; fd = open(name, O_RDWR); if (fd < 0) { perror("open"); return 1; } dumpstat(name, fd); if (msglen) do_msg(fd, msglen); if (readcount) do_read(fd, readcount); close(fd); return 0; }
path: root/net/ipv6/tcpv6_offload.c
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authorLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-29 13:50:06 -0800
commit39cb2c9a316e77f6dfba96c543e55b6672d5a37e (patch)
tree98fe974ee4e20121253de7f61fc8d01bdb3821c1 /net/ipv6/tcpv6_offload.c
parent2c5d9555d6d937966d79d4c6529a5f7b9206e405 (diff)
drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()
I've seen this trigger twice now, where the i915_gem_object_to_ggtt() call in intel_unpin_fb_obj() returns NULL, resulting in an oops immediately afterwards as the (inlined) call to i915_vma_unpin_fence() tries to dereference it. It seems to be some race condition where the object is going away at shutdown time, since both times happened when shutting down the X server. The call chains were different: - VT ioctl(KDSETMODE, KD_TEXT): intel_cleanup_plane_fb+0x5b/0xa0 [i915] 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/ipv6/tcpv6_offload.c')