February 2025 - Linux-stable-mirror

FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020538-unmoving-shelving-20de@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

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FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020537-dominoes-catty-42c4@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

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FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020535-spender-graveness-c15e@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

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FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020534-imposing-hacksaw-eff6@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

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0
0 0

FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 6.6-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020533-maturity-audacious-3a1f@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

1
0
0 0

FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 6.12-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020532-component-gratified-8153@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

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FAILED: patch "[PATCH] btrfs: fix double accounting race when extent_writepage_io()" failed to apply to 6.13-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.13-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.13.y git checkout FETCH_HEAD git cherry-pick -x 8bf334beb3496da3c3fbf3daf3856f7eec70dacc # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020531-uneasily-twitch-9e6b@gregkh' --subject-prefix 'PATCH 6.13.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 8bf334beb3496da3c3fbf3daf3856f7eec70dacc Mon Sep 17 00:00:00 2001 From: Qu Wenruo <wqu(a)suse.com> Date: Thu, 12 Dec 2024 16:43:56 +1030 Subject: [PATCH] btrfs: fix double accounting race when extent_writepage_io() failed [BUG] If submit_one_sector() failed inside extent_writepage_io() for sector size < page size cases (e.g. 4K sector size and 64K page size), then we can hit double ordered extent accounting error. This should be very rare, as submit_one_sector() only fails when we failed to grab the extent map, and such extent map should exist inside the memory and has been pinned. [CAUSE] For example we have the following folio layout: 0 4K 32K 48K 60K 64K |//| |//////| |///| Where |///| is the dirty range we need to writeback. The 3 different dirty ranges are submitted for regular COW. Now we hit the following sequence: - submit_one_sector() returned 0 for [0, 4K) - submit_one_sector() returned 0 for [32K, 48K) - submit_one_sector() returned error for [60K, 64K) - btrfs_mark_ordered_io_finished() called for the whole folio This will mark the following ranges as finished: * [0, 4K) * [32K, 48K) Both ranges have their IO already submitted, this cleanup will lead to double accounting. * [60K, 64K) That's the correct cleanup. The only good news is, this error is only theoretical, as the target extent map is always pinned, thus we should directly grab it from memory, other than reading it from the disk. [FIX] Instead of calling btrfs_mark_ordered_io_finished() for the whole folio range, which can touch ranges we should not touch, instead move the error handling inside extent_writepage_io(). So that we can cleanup exact sectors that ought to be submitted but failed. This provides much more accurate cleanup, avoiding the double accounting. CC: stable(a)vger.kernel.org # 5.15+ Signed-off-by: Qu Wenruo <wqu(a)suse.com> Signed-off-by: David Sterba <dsterba(a)suse.com> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bc2bd103c8cc..5014134b9aa2 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -1420,6 +1420,7 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, struct btrfs_fs_info *fs_info = inode->root->fs_info; unsigned long range_bitmap = 0; bool submitted_io = false; + bool error = false; const u64 folio_start = folio_pos(folio); u64 cur; int bit; @@ -1462,11 +1463,26 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, break; } ret = submit_one_sector(inode, folio, cur, bio_ctrl, i_size); - if (ret < 0) - goto out; + if (unlikely(ret < 0)) { + /* + * bio_ctrl may contain a bio crossing several folios. + * Submit it immediately so that the bio has a chance + * to finish normally, other than marked as error. + */ + submit_one_bio(bio_ctrl); + /* + * Failed to grab the extent map which should be very rare. + * Since there is no bio submitted to finish the ordered + * extent, we have to manually finish this sector. + */ + btrfs_mark_ordered_io_finished(inode, folio, cur, + fs_info->sectorsize, false); + error = true; + continue; + } submitted_io = true; } -out: + /* * If we didn't submitted any sector (>= i_size), folio dirty get * cleared but PAGECACHE_TAG_DIRTY is not cleared (only cleared @@ -1474,8 +1490,11 @@ static noinline_for_stack int extent_writepage_io(struct btrfs_inode *inode, * * Here we set writeback and clear for the range. If the full folio * is no longer dirty then we clear the PAGECACHE_TAG_DIRTY tag. + * + * If we hit any error, the corresponding sector will still be dirty + * thus no need to clear PAGECACHE_TAG_DIRTY. */ - if (!submitted_io) { + if (!submitted_io && !error) { btrfs_folio_set_writeback(fs_info, folio, start, len); btrfs_folio_clear_writeback(fs_info, folio, start, len); } @@ -1495,7 +1514,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl { struct btrfs_inode *inode = BTRFS_I(folio->mapping->host); struct btrfs_fs_info *fs_info = inode->root->fs_info; - const u64 page_start = folio_pos(folio); int ret; size_t pg_offset; loff_t i_size = i_size_read(&inode->vfs_inode); @@ -1538,10 +1556,6 @@ static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl bio_ctrl->wbc->nr_to_write--; - if (ret) - btrfs_mark_ordered_io_finished(inode, folio, - page_start, PAGE_SIZE, !ret); - done: if (ret < 0) mapping_set_error(folio->mapping, ret); @@ -2314,11 +2328,8 @@ void extent_write_locked_range(struct inode *inode, const struct folio *locked_f if (ret == 1) goto next_page; - if (ret) { - btrfs_mark_ordered_io_finished(BTRFS_I(inode), folio, - cur, cur_len, !ret); + if (ret) mapping_set_error(mapping, ret); - } btrfs_folio_end_lock(fs_info, folio, cur, cur_len); if (ret < 0) found_error = true;

4 months, 1 week

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0
0 0

FAILED: patch "[PATCH] memcg: fix soft lockup in the OOM process" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x ade81479c7dda1ce3eedb215c78bc615bbd04f06 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020518-carnage-deflator-99f2@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ade81479c7dda1ce3eedb215c78bc615bbd04f06 Mon Sep 17 00:00:00 2001 From: Chen Ridong <chenridong(a)huawei.com> Date: Tue, 24 Dec 2024 02:52:38 +0000 Subject: [PATCH] memcg: fix soft lockup in the OOM process MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A soft lockup issue was found in the product with about 56,000 tasks were in the OOM cgroup, it was traversing them when the soft lockup was triggered. watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [VM Thread:1503066] CPU: 2 PID: 1503066 Comm: VM Thread Kdump: loaded Tainted: G Hardware name: Huawei Cloud OpenStack Nova, BIOS RIP: 0010:console_unlock+0x343/0x540 RSP: 0000:ffffb751447db9a0 EFLAGS: 00000247 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000247 RBP: ffffffffafc71f90 R08: 0000000000000000 R09: 0000000000000040 R10: 0000000000000080 R11: 0000000000000000 R12: ffffffffafc74bd0 R13: ffffffffaf60a220 R14: 0000000000000247 R15: 0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2fe6ad91f0 CR3: 00000004b2076003 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vprintk_emit+0x193/0x280 printk+0x52/0x6e dump_task+0x114/0x130 mem_cgroup_scan_tasks+0x76/0x100 dump_header+0x1fe/0x210 oom_kill_process+0xd1/0x100 out_of_memory+0x125/0x570 mem_cgroup_out_of_memory+0xb5/0xd0 try_charge+0x720/0x770 mem_cgroup_try_charge+0x86/0x180 mem_cgroup_try_charge_delay+0x1c/0x40 do_anonymous_page+0xb5/0x390 handle_mm_fault+0xc4/0x1f0 This is because thousands of processes are in the OOM cgroup, it takes a long time to traverse all of them. As a result, this lead to soft lockup in the OOM process. To fix this issue, call 'cond_resched' in the 'mem_cgroup_scan_tasks' function per 1000 iterations. For global OOM, call 'touch_softlockup_watchdog' per 1000 iterations to avoid this issue. Link: https://lkml.kernel.org/r/20241224025238.3768787-1-chenridong@huaweicloud.c… Fixes: 9cbb78bb3143 ("mm, memcg: introduce own oom handler to iterate only over its own threads") Signed-off-by: Chen Ridong <chenridong(a)huawei.com> Acked-by: Michal Hocko <mhocko(a)suse.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Muchun Song <songmuchun(a)bytedance.com> Cc: Michal Koutný <mkoutny(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 65fb5eee1466..46f8b372d212 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1161,6 +1161,7 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, { struct mem_cgroup *iter; int ret = 0; + int i = 0; BUG_ON(mem_cgroup_is_root(memcg)); @@ -1169,8 +1170,12 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, struct task_struct *task; css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it); - while (!ret && (task = css_task_iter_next(&it))) + while (!ret && (task = css_task_iter_next(&it))) { + /* Avoid potential softlockup warning */ + if ((++i & 1023) == 0) + cond_resched(); ret = fn(task, arg); + } css_task_iter_end(&it); if (ret) { mem_cgroup_iter_break(memcg, iter); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1c485beb0b93..044ebab2c941 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -44,6 +44,7 @@ #include <linux/init.h> #include <linux/mmu_notifier.h> #include <linux/cred.h> +#include <linux/nmi.h> #include <asm/tlb.h> #include "internal.h" @@ -430,10 +431,15 @@ static void dump_tasks(struct oom_control *oc) mem_cgroup_scan_tasks(oc->memcg, dump_task, oc); else { struct task_struct *p; + int i = 0; rcu_read_lock(); - for_each_process(p) + for_each_process(p) { + /* Avoid potential softlockup warning */ + if ((++i & 1023) == 0) + touch_softlockup_watchdog(); dump_task(p, oc); + } rcu_read_unlock(); } }

4 months, 1 week

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FAILED: patch "[PATCH] memcg: fix soft lockup in the OOM process" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x ade81479c7dda1ce3eedb215c78bc615bbd04f06 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020517-confident-sterile-7acb@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ade81479c7dda1ce3eedb215c78bc615bbd04f06 Mon Sep 17 00:00:00 2001 From: Chen Ridong <chenridong(a)huawei.com> Date: Tue, 24 Dec 2024 02:52:38 +0000 Subject: [PATCH] memcg: fix soft lockup in the OOM process MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A soft lockup issue was found in the product with about 56,000 tasks were in the OOM cgroup, it was traversing them when the soft lockup was triggered. watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [VM Thread:1503066] CPU: 2 PID: 1503066 Comm: VM Thread Kdump: loaded Tainted: G Hardware name: Huawei Cloud OpenStack Nova, BIOS RIP: 0010:console_unlock+0x343/0x540 RSP: 0000:ffffb751447db9a0 EFLAGS: 00000247 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000247 RBP: ffffffffafc71f90 R08: 0000000000000000 R09: 0000000000000040 R10: 0000000000000080 R11: 0000000000000000 R12: ffffffffafc74bd0 R13: ffffffffaf60a220 R14: 0000000000000247 R15: 0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2fe6ad91f0 CR3: 00000004b2076003 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vprintk_emit+0x193/0x280 printk+0x52/0x6e dump_task+0x114/0x130 mem_cgroup_scan_tasks+0x76/0x100 dump_header+0x1fe/0x210 oom_kill_process+0xd1/0x100 out_of_memory+0x125/0x570 mem_cgroup_out_of_memory+0xb5/0xd0 try_charge+0x720/0x770 mem_cgroup_try_charge+0x86/0x180 mem_cgroup_try_charge_delay+0x1c/0x40 do_anonymous_page+0xb5/0x390 handle_mm_fault+0xc4/0x1f0 This is because thousands of processes are in the OOM cgroup, it takes a long time to traverse all of them. As a result, this lead to soft lockup in the OOM process. To fix this issue, call 'cond_resched' in the 'mem_cgroup_scan_tasks' function per 1000 iterations. For global OOM, call 'touch_softlockup_watchdog' per 1000 iterations to avoid this issue. Link: https://lkml.kernel.org/r/20241224025238.3768787-1-chenridong@huaweicloud.c… Fixes: 9cbb78bb3143 ("mm, memcg: introduce own oom handler to iterate only over its own threads") Signed-off-by: Chen Ridong <chenridong(a)huawei.com> Acked-by: Michal Hocko <mhocko(a)suse.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Muchun Song <songmuchun(a)bytedance.com> Cc: Michal Koutný <mkoutny(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 65fb5eee1466..46f8b372d212 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1161,6 +1161,7 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, { struct mem_cgroup *iter; int ret = 0; + int i = 0; BUG_ON(mem_cgroup_is_root(memcg)); @@ -1169,8 +1170,12 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, struct task_struct *task; css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it); - while (!ret && (task = css_task_iter_next(&it))) + while (!ret && (task = css_task_iter_next(&it))) { + /* Avoid potential softlockup warning */ + if ((++i & 1023) == 0) + cond_resched(); ret = fn(task, arg); + } css_task_iter_end(&it); if (ret) { mem_cgroup_iter_break(memcg, iter); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1c485beb0b93..044ebab2c941 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -44,6 +44,7 @@ #include <linux/init.h> #include <linux/mmu_notifier.h> #include <linux/cred.h> +#include <linux/nmi.h> #include <asm/tlb.h> #include "internal.h" @@ -430,10 +431,15 @@ static void dump_tasks(struct oom_control *oc) mem_cgroup_scan_tasks(oc->memcg, dump_task, oc); else { struct task_struct *p; + int i = 0; rcu_read_lock(); - for_each_process(p) + for_each_process(p) { + /* Avoid potential softlockup warning */ + if ((++i & 1023) == 0) + touch_softlockup_watchdog(); dump_task(p, oc); + } rcu_read_unlock(); } }

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FAILED: patch "[PATCH] memcg: fix soft lockup in the OOM process" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x ade81479c7dda1ce3eedb215c78bc615bbd04f06 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025020516-fable-crane-ab09@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From ade81479c7dda1ce3eedb215c78bc615bbd04f06 Mon Sep 17 00:00:00 2001 From: Chen Ridong <chenridong(a)huawei.com> Date: Tue, 24 Dec 2024 02:52:38 +0000 Subject: [PATCH] memcg: fix soft lockup in the OOM process MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A soft lockup issue was found in the product with about 56,000 tasks were in the OOM cgroup, it was traversing them when the soft lockup was triggered. watchdog: BUG: soft lockup - CPU#2 stuck for 23s! [VM Thread:1503066] CPU: 2 PID: 1503066 Comm: VM Thread Kdump: loaded Tainted: G Hardware name: Huawei Cloud OpenStack Nova, BIOS RIP: 0010:console_unlock+0x343/0x540 RSP: 0000:ffffb751447db9a0 EFLAGS: 00000247 ORIG_RAX: ffffffffffffff13 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000247 RBP: ffffffffafc71f90 R08: 0000000000000000 R09: 0000000000000040 R10: 0000000000000080 R11: 0000000000000000 R12: ffffffffafc74bd0 R13: ffffffffaf60a220 R14: 0000000000000247 R15: 0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2fe6ad91f0 CR3: 00000004b2076003 CR4: 0000000000360ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vprintk_emit+0x193/0x280 printk+0x52/0x6e dump_task+0x114/0x130 mem_cgroup_scan_tasks+0x76/0x100 dump_header+0x1fe/0x210 oom_kill_process+0xd1/0x100 out_of_memory+0x125/0x570 mem_cgroup_out_of_memory+0xb5/0xd0 try_charge+0x720/0x770 mem_cgroup_try_charge+0x86/0x180 mem_cgroup_try_charge_delay+0x1c/0x40 do_anonymous_page+0xb5/0x390 handle_mm_fault+0xc4/0x1f0 This is because thousands of processes are in the OOM cgroup, it takes a long time to traverse all of them. As a result, this lead to soft lockup in the OOM process. To fix this issue, call 'cond_resched' in the 'mem_cgroup_scan_tasks' function per 1000 iterations. For global OOM, call 'touch_softlockup_watchdog' per 1000 iterations to avoid this issue. Link: https://lkml.kernel.org/r/20241224025238.3768787-1-chenridong@huaweicloud.c… Fixes: 9cbb78bb3143 ("mm, memcg: introduce own oom handler to iterate only over its own threads") Signed-off-by: Chen Ridong <chenridong(a)huawei.com> Acked-by: Michal Hocko <mhocko(a)suse.com> Cc: Roman Gushchin <roman.gushchin(a)linux.dev> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: Shakeel Butt <shakeelb(a)google.com> Cc: Muchun Song <songmuchun(a)bytedance.com> Cc: Michal Koutný <mkoutny(a)suse.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 65fb5eee1466..46f8b372d212 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1161,6 +1161,7 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, { struct mem_cgroup *iter; int ret = 0; + int i = 0; BUG_ON(mem_cgroup_is_root(memcg)); @@ -1169,8 +1170,12 @@ void mem_cgroup_scan_tasks(struct mem_cgroup *memcg, struct task_struct *task; css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it); - while (!ret && (task = css_task_iter_next(&it))) + while (!ret && (task = css_task_iter_next(&it))) { + /* Avoid potential softlockup warning */ + if ((++i & 1023) == 0) + cond_resched(); ret = fn(task, arg); + } css_task_iter_end(&it); if (ret) { mem_cgroup_iter_break(memcg, iter); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 1c485beb0b93..044ebab2c941 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -44,6 +44,7 @@ #include <linux/init.h> #include <linux/mmu_notifier.h> #include <linux/cred.h> +#include <linux/nmi.h> #include <asm/tlb.h> #include "internal.h" @@ -430,10 +431,15 @@ static void dump_tasks(struct oom_control *oc) mem_cgroup_scan_tasks(oc->memcg, dump_task, oc); else { struct task_struct *p; + int i = 0; rcu_read_lock(); - for_each_process(p) + for_each_process(p) { + /* Avoid potential softlockup warning */ + if ((++i & 1023) == 0) + touch_softlockup_watchdog(); dump_task(p, oc); + } rcu_read_unlock(); } }

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