The patch titled buffer_head-remove-redundant-test-from-wait_on_buffer-fix has been added to the -mm tree. Its filename is buffer_head-remove-redundant-test-from-wait_on_buffer-fix.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: buffer_head-remove-redundant-test-from-wait_on_buffer-fix From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> restore the test Cc: Jens Axboe <jens.axboe@xxxxxxxxxx> Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx> Cc: Richard Kennedy <richard@xxxxxxxxxxxxxxx> Cc: Jeff Mahoney <jeffm@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/buffer.c | 6 ++++++ include/linux/buffer_head.h | 7 ++++++- 2 files changed, 12 insertions(+), 1 deletion(-) diff -puN fs/buffer.c~buffer_head-remove-redundant-test-from-wait_on_buffer-fix fs/buffer.c --- a/fs/buffer.c~buffer_head-remove-redundant-test-from-wait_on_buffer-fix +++ a/fs/buffer.c @@ -90,6 +90,12 @@ EXPORT_SYMBOL(unlock_buffer); */ void __wait_on_buffer(struct buffer_head * bh) { + /* + * Calling wait_on_buffer() against a zero-ref buffer is a nasty bug + * because it will almost always "work". However this buffer can be + * reclaimed at any time. So check for it. + */ + VM_BUG_ON(atomic_read(&bh->b_count) == 0); wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(__wait_on_buffer); diff -puN include/linux/buffer_head.h~buffer_head-remove-redundant-test-from-wait_on_buffer-fix include/linux/buffer_head.h --- a/include/linux/buffer_head.h~buffer_head-remove-redundant-test-from-wait_on_buffer-fix +++ a/include/linux/buffer_head.h @@ -305,10 +305,15 @@ map_bh(struct buffer_head *bh, struct su bh->b_size = sb->s_blocksize; } +/* + * Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into + * __wait_on_buffer() just to trip a debug check. Because debug code in inline + * functions is bloaty. + */ static inline void wait_on_buffer(struct buffer_head *bh) { might_sleep(); - if (buffer_locked(bh)) + if (buffer_locked(bh) || atomic_read(&bh->b_count) == 0) __wait_on_buffer(bh); } _ Patches currently in -mm which might be from akpm@xxxxxxxxxxxxxxxxxxxx are origin.patch linux-next.patch next-remove-localversion.patch i-need-old-gcc.patch arch-x86-crypto-aesni-intel_asms-still-busted.patch include-linux-fsh-complete-hexification-of-fmode_-constants.patch drivers-video-efifbc-framebuffer-for-nvidia-9400m-in-macbook-pro-51-fix.patch intel-agpc-fix-crash-when-accessing-nonexistent-gtt-entries-in-i915-checkpatch-fixes.patch iio-iio_get_new_idr_val-return-negative-value-on-failure-fix.patch drivers-acpi-use-kasprintf-fix.patch acpi_pad-processor_aggregator-name-too-long-fix.patch arch-arm-include-asm-elfh-forward-declare-the-task-struct.patch cifs-provide-user-with-a-hint-when-name-resolution-fails-fix.patch jfs-free-sbi-memory-in-error-path.patch fs-fscache-object-listc-fix-warning-on-32-bit.patch of-gpio-implement-gpiolib-notifier-hooks-fix.patch of-gpio-implement-gpiolib-notifier-hooks-fix-fix2.patch hpet-factor-timer-allocate-from-open-fix.patch led-driver-for-the-soekris-net5501-board-checkpatch-fixes.patch leds-route-kbd-leds-through-the-generic-leds-layer-fix.patch gpio-add-support-for-janz-vmod-ttl-digital-io-module-fix.patch 3x59x-fix-pci-resource-management.patch backlight-add-s6e63m0-amoled-lcd-panel-driver-checkpatch-fixes.patch serial-timbuart-make-sure-last-byte-is-sent-when-port-is-closed-fix.patch kernel-irq-managec-add-raise_threaded_irq-fix.patch max3100-to_max3100_port-small-style-fixes-fix.patch mm-export-unusable-free-space-index-via-proc-unusable_index-fix-fix-2.patch mm-compaction-direct-compact-when-a-high-order-allocation-fails-reject-fix.patch vmstat-fix-build-errors-when-proc_fs-is-disabled-checkpatch-fixes.patch mm-compaction-do-not-display-compaction-related-stats-when-config_compaction-fix.patch mm-compaction-do-not-display-compaction-related-stats-when-config_compaction-fix-fix-2.patch buffer_head-remove-redundant-test-from-wait_on_buffer-fix.patch wait_on_buffer-remove-the-buffer_locked-test.patch frv-extend-gdbstub-to-support-more-features-of-gdb-fix.patch frv-duplicate-output_buffer-of-e03-checkpatch-fixes.patch kernel-wide-replace-ushort_max-short_max-and-short_min-with-ushrt_max-shrt_max-and-shrt_min-fix.patch firmware-loader-use-statically-initialized-data-attribute-fix.patch firmware-loader-use-statically-initialized-data-attribute-fix-fix.patch davinci-mmc-updates-to-suspend-resume-implementation-checkpatch-fixes.patch checkpatch-add-check-for-too-short-kconfig-descriptions-checkpatch-fixes.patch hwmon-driver-for-ti-tmp102-temperature-sensor.patch hwmon-driver-for-ti-tmp102-temperature-sensor-fix.patch hwmon-add-ti-ads7871-a-d-converter-driver-checkpatch-fixes.patch rtc-mxc-remove-unnecessary-clock-source-for-rtc-subsystem.patch gpiolib-make-names-array-and-its-values-const-fix.patch memcg-oom-kill-disable-and-oom-status-update-checkpatch-fixes.patch memcg-move-charge-of-file-pages-fix.patch proc-turn-signal_struct-count-into-int-nr_threads-checkpatch-fixes.patch fault-injection-add-cpu-notifier-error-injection-module-fix.patch delay-accounting-re-implement-c-for-getdelaysc-to-report-information-on-a-target-command-checkpatch-fixes.patch panic-allow-taint-flag-for-warnings-to-be-changed-from-taint_warn-checkpatch-fixes.patch x86_32-use-asm-generic-scatterlisth.patch reiser4-export-remove_from_page_cache-fix.patch reiser4.patch reiser4-writeback_inodes-implementation-fix.patch reiser4-fixups.patch reiser4-broke.patch slab-leaks3-default-y.patch put_bh-debug.patch getblk-handle-2tb-devices.patch getblk-handle-2tb-devices-fix.patch notify_change-callers-must-hold-i_mutex.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html