December 2024 - Linux-stable-mirror

[PATCH V4] mm/gup: Clear the LRU flag of a page before adding to LRU batch

by yangge1116＠126.com

From: yangge <yangge1116(a)126.com> If a large number of CMA memory are configured in system (for example, the CMA memory accounts for 50% of the system memory), starting a virtual virtual machine with device passthrough, it will call pin_user_pages_remote(..., FOLL_LONGTERM, ...) to pin memory. Normally if a page is present and in CMA area, pin_user_pages_remote() will migrate the page from CMA area to non-CMA area because of FOLL_LONGTERM flag. But the current code will cause the … [View More]migration failure due to unexpected page refcounts, and eventually cause the virtual machine fail to start. If a page is added in LRU batch, its refcount increases one, remove the page from LRU batch decreases one. Page migration requires the page is not referenced by others except page mapping. Before migrating a page, we should try to drain the page from LRU batch in case the page is in it, however, folio_test_lru() is not sufficient to tell whether the page is in LRU batch or not, if the page is in LRU batch, the migration will fail. To solve the problem above, we modify the logic of adding to LRU batch. Before adding a page to LRU batch, we clear the LRU flag of the page so that we can check whether the page is in LRU batch by folio_test_lru(page). It's quite valuable, because likely we don't want to blindly drain the LRU batch simply because there is some unexpected reference on a page, as described above. This change makes the LRU flag of a page invisible for longer, which may impact some programs. For example, as long as a page is on a LRU batch, we cannot isolate it, and we cannot check if it's an LRU page. Further, a page can now only be on exactly one LRU batch. This doesn't seem to matter much, because a new page is allocated from buddy and added to the lru batch, or be isolated, it's LRU flag may also be invisible for a long time. Fixes: 9a4e9f3b2d73 ("mm: update get_user_pages_longterm to migrate pages allocated from CMA region") Cc: <stable(a)vger.kernel.org> Signed-off-by: yangge <yangge1116(a)126.com> --- mm/swap.c | 43 +++++++++++++++++++++++++++++++------------ 1 file changed, 31 insertions(+), 12 deletions(-) V4: Adjust commit message according to David's comments V3: Add fixes tag V2: Adjust code and commit message according to David's comments diff --git a/mm/swap.c b/mm/swap.c index dc205bd..9caf6b0 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -211,10 +211,6 @@ static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn) for (i = 0; i < folio_batch_count(fbatch); i++) { struct folio *folio = fbatch->folios[i]; - /* block memcg migration while the folio moves between lru */ - if (move_fn != lru_add_fn && !folio_test_clear_lru(folio)) - continue; - folio_lruvec_relock_irqsave(folio, &lruvec, &flags); move_fn(lruvec, folio); @@ -255,11 +251,16 @@ static void lru_move_tail_fn(struct lruvec *lruvec, struct folio *folio) void folio_rotate_reclaimable(struct folio *folio) { if (!folio_test_locked(folio) && !folio_test_dirty(folio) && - !folio_test_unevictable(folio) && folio_test_lru(folio)) { + !folio_test_unevictable(folio)) { struct folio_batch *fbatch; unsigned long flags; folio_get(folio); + if (!folio_test_clear_lru(folio)) { + folio_put(folio); + return; + } + local_lock_irqsave(&lru_rotate.lock, flags); fbatch = this_cpu_ptr(&lru_rotate.fbatch); folio_batch_add_and_move(fbatch, folio, lru_move_tail_fn); @@ -352,11 +353,15 @@ static void folio_activate_drain(int cpu) void folio_activate(struct folio *folio) { - if (folio_test_lru(folio) && !folio_test_active(folio) && - !folio_test_unevictable(folio)) { + if (!folio_test_active(folio) && !folio_test_unevictable(folio)) { struct folio_batch *fbatch; folio_get(folio); + if (!folio_test_clear_lru(folio)) { + folio_put(folio); + return; + } + local_lock(&cpu_fbatches.lock); fbatch = this_cpu_ptr(&cpu_fbatches.activate); folio_batch_add_and_move(fbatch, folio, folio_activate_fn); @@ -700,6 +705,11 @@ void deactivate_file_folio(struct folio *folio) return; folio_get(folio); + if (!folio_test_clear_lru(folio)) { + folio_put(folio); + return; + } + local_lock(&cpu_fbatches.lock); fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate_file); folio_batch_add_and_move(fbatch, folio, lru_deactivate_file_fn); @@ -716,11 +726,16 @@ void deactivate_file_folio(struct folio *folio) */ void folio_deactivate(struct folio *folio) { - if (folio_test_lru(folio) && !folio_test_unevictable(folio) && - (folio_test_active(folio) || lru_gen_enabled())) { + if (!folio_test_unevictable(folio) && (folio_test_active(folio) || + lru_gen_enabled())) { struct folio_batch *fbatch; folio_get(folio); + if (!folio_test_clear_lru(folio)) { + folio_put(folio); + return; + } + local_lock(&cpu_fbatches.lock); fbatch = this_cpu_ptr(&cpu_fbatches.lru_deactivate); folio_batch_add_and_move(fbatch, folio, lru_deactivate_fn); @@ -737,12 +752,16 @@ void folio_deactivate(struct folio *folio) */ void folio_mark_lazyfree(struct folio *folio) { - if (folio_test_lru(folio) && folio_test_anon(folio) && - folio_test_swapbacked(folio) && !folio_test_swapcache(folio) && - !folio_test_unevictable(folio)) { + if (folio_test_anon(folio) && folio_test_swapbacked(folio) && + !folio_test_swapcache(folio) && !folio_test_unevictable(folio)) { struct folio_batch *fbatch; folio_get(folio); + if (!folio_test_clear_lru(folio)) { + folio_put(folio); + return; + } + local_lock(&cpu_fbatches.lock); fbatch = this_cpu_ptr(&cpu_fbatches.lru_lazyfree); folio_batch_add_and_move(fbatch, folio, lru_lazyfree_fn); -- 2.7.4 [View Less]

3 days, 6 hours

3
9
0 0

[PATCH] hfs/hfsplus: fix slab-out-of-bounds in hfs_bnode_read_key

by Vasiliy Kovalev

Syzbot reported an issue in hfs subsystem: BUG: KASAN: slab-out-of-bounds in memcpy_from_page include/linux/highmem.h:423 [inline] BUG: KASAN: slab-out-of-bounds in hfs_bnode_read fs/hfs/bnode.c:35 [inline] BUG: KASAN: slab-out-of-bounds in hfs_bnode_read_key+0x314/0x450 fs/hfs/bnode.c:70 Write of size 94 at addr ffff8880123cd100 by task syz-executor237/5102 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 … [View More]print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 kasan_check_range+0x282/0x290 mm/kasan/generic.c:189 __asan_memcpy+0x40/0x70 mm/kasan/shadow.c:106 memcpy_from_page include/linux/highmem.h:423 [inline] hfs_bnode_read fs/hfs/bnode.c:35 [inline] hfs_bnode_read_key+0x314/0x450 fs/hfs/bnode.c:70 hfs_brec_insert+0x7f3/0xbd0 fs/hfs/brec.c:159 hfs_cat_create+0x41d/0xa50 fs/hfs/catalog.c:118 hfs_mkdir+0x6c/0xe0 fs/hfs/dir.c:232 vfs_mkdir+0x2f9/0x4f0 fs/namei.c:4257 do_mkdirat+0x264/0x3a0 fs/namei.c:4280 __do_sys_mkdir fs/namei.c:4300 [inline] __se_sys_mkdir fs/namei.c:4298 [inline] __x64_sys_mkdir+0x6c/0x80 fs/namei.c:4298 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fbdd6057a99 Add a check for key length in hfs_bnode_read_key to prevent out-of-bounds memory access. If the key length is invalid, the key buffer is cleared, improving stability and reliability. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+5f3a973ed3dfb85a6683(a)syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5f3a973ed3dfb85a6683 Cc: stable(a)vger.kernel.org Signed-off-by: Vasiliy Kovalev <kovalev(a)altlinux.org> --- fs/hfs/bnode.c | 6 ++++++ fs/hfsplus/bnode.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c index 6add6ebfef8967..cb823a8a6ba960 100644 --- a/fs/hfs/bnode.c +++ b/fs/hfs/bnode.c @@ -67,6 +67,12 @@ void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off) else key_len = tree->max_key_len + 1; + if (key_len > sizeof(hfs_btree_key) || key_len < 1) { + memset(key, 0, sizeof(hfs_btree_key)); + pr_err("hfs: Invalid key length: %d\n", key_len); + return; + } + hfs_bnode_read(node, key, off, key_len); } diff --git a/fs/hfsplus/bnode.c b/fs/hfsplus/bnode.c index 87974d5e679156..079ea80534f7de 100644 --- a/fs/hfsplus/bnode.c +++ b/fs/hfsplus/bnode.c @@ -67,6 +67,12 @@ void hfs_bnode_read_key(struct hfs_bnode *node, void *key, int off) else key_len = tree->max_key_len + 2; + if (key_len > sizeof(hfsplus_btree_key) || key_len < 1) { + memset(key, 0, sizeof(hfsplus_btree_key)); + pr_err("hfsplus: Invalid key length: %d\n", key_len); + return; + } + hfs_bnode_read(node, key, off, key_len); } -- 2.33.8 [View Less]

4 days, 22 hours

9
18
0 0

[PATCH 1/2] drm/i915: Schedule the HPD poll init work on an unbound workqueue

by Imre Deak

Disabling HPD polling from i915_hpd_poll_init_work() involves probing all display connectors explicitly to account for lost hotplug interrupts. On some platforms (mostly pre-ICL) with HDMI connectors the I2C EDID bit-banging using udelay() triggers in turn the workqueue: i915_hpd_poll_init_work [i915] hogged CPU for >10000us 4 times, consider switching to WQ_UNBOUND warning. Fix the above by scheduling i915_hpd_poll_init_work() on a WQ_UNBOUND workqueue. It's ok to use a system WQ, since … [View More]

6 days, 2 hours

4
5
0 0

[PATCH v1 1/1] mfd: rk8xx: Fix shutdown handler

by Sebastian Reichel

When I converted rk808 to device managed resources I converted the rk808 specific pm_power_off handler to devm_register_sys_off_handler() using SYS_OFF_MODE_POWER_OFF_PREPARE, which is allowed to sleep. I did this because the driver's poweroff function makes use of regmap and the backend of that might sleep. But the PMIC poweroff function will kill off the board power and the kernel does some extra steps after the prepare handler. Thus the prepare handler should not be used for the PMIC's … [View More]poweroff routine. Instead the normal SYS_OFF_MODE_POWER_OFF phase should be used. The old pm_power_off method is also being called from there, so this would have been a cleaner conversion anyways. But it still makes sense to investigate the sleep handling and check if there are any issues. Apparently the Rockchip and Meson I2C drivers (the only platforms using the PMICs handled by this driver) both have support for atomic transfers and thus may be called from the proper poweroff context. Things are different on the SPI side. That is so far only used by rk806 and that one is only used by Rockchip RK3588. Unfortunately the Rockchip SPI driver does not support atomic transfers. That means using the normal POWER_OFF handler would introduce the following error splash during shutdown on all RK3588 boards currently supported upstream: [ 13.761353] ------------[ cut here ]------------ [ 13.761764] Voluntary context switch within RCU read-side critical section! [ 13.761776] WARNING: CPU: 0 PID: 1 at kernel/rcu/tree_plugin.h:330 rcu_note_context_switch+0x3ac/0x404 [ 13.763219] Modules linked in: [ 13.763498] CPU: 0 UID: 0 PID: 1 Comm: systemd-shutdow Not tainted 6.10.0-12284-g2818a9a19514 #1499 [ 13.764297] Hardware name: Rockchip RK3588 EVB1 V10 Board (DT) [ 13.764812] pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 13.765427] pc : rcu_note_context_switch+0x3ac/0x404 [ 13.765871] lr : rcu_note_context_switch+0x3ac/0x404 [ 13.766314] sp : ffff800084f4b5b0 [ 13.766609] x29: ffff800084f4b5b0 x28: ffff00040139b800 x27: 00007dfb4439ae80 [ 13.767245] x26: ffff00040139bc80 x25: 0000000000000000 x24: ffff800082118470 [ 13.767880] x23: 0000000000000000 x22: ffff000400300000 x21: ffff000400300000 [ 13.768515] x20: ffff800083a9d600 x19: ffff0004fee48600 x18: fffffffffffed448 [ 13.769151] x17: 000000040044ffff x16: 005000f2b5503510 x15: 0000000000000048 [ 13.769787] x14: fffffffffffed490 x13: ffff80008473b3c0 x12: 0000000000000900 [ 13.770421] x11: 0000000000000300 x10: ffff800084797bc0 x9 : ffff80008473b3c0 [ 13.771057] x8 : 00000000ffffefff x7 : ffff8000847933c0 x6 : 0000000000000300 [ 13.771692] x5 : 0000000000000301 x4 : 40000000fffff300 x3 : 0000000000000000 [ 13.772328] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff000400300000 [ 13.772964] Call trace: [ 13.773184] rcu_note_context_switch+0x3ac/0x404 [ 13.773598] __schedule+0x94/0xb0c [ 13.773907] schedule+0x34/0x104 [ 13.774198] schedule_timeout+0x84/0xfc [ 13.774544] wait_for_completion_timeout+0x78/0x14c [ 13.774980] spi_transfer_one_message+0x588/0x690 [ 13.775403] __spi_pump_transfer_message+0x19c/0x4ec [ 13.775846] __spi_sync+0x2a8/0x3c4 [ 13.776161] spi_write_then_read+0x120/0x208 [ 13.776543] rk806_spi_bus_read+0x54/0x88 [ 13.776905] _regmap_raw_read+0xec/0x16c [ 13.777257] _regmap_bus_read+0x44/0x7c [ 13.777601] _regmap_read+0x60/0xd8 [ 13.777915] _regmap_update_bits+0xf4/0x13c [ 13.778289] regmap_update_bits_base+0x64/0x98 [ 13.778686] rk808_power_off+0x70/0xfc [ 13.779024] sys_off_notify+0x40/0x6c [ 13.779356] atomic_notifier_call_chain+0x60/0x90 [ 13.779776] do_kernel_power_off+0x54/0x6c [ 13.780146] machine_power_off+0x18/0x24 [ 13.780499] kernel_power_off+0x70/0x7c [ 13.780845] __do_sys_reboot+0x210/0x270 [ 13.781198] __arm64_sys_reboot+0x24/0x30 [ 13.781558] invoke_syscall+0x48/0x10c [ 13.781897] el0_svc_common+0x3c/0xe8 [ 13.782228] do_el0_svc+0x20/0x2c [ 13.782528] el0_svc+0x34/0xd8 [ 13.782806] el0t_64_sync_handler+0x120/0x12c [ 13.783197] el0t_64_sync+0x190/0x194 [ 13.783527] ---[ end trace 0000000000000000 ]--- To avoid this we keep the SYS_OFF_MODE_POWER_OFF_PREPARE handler for the SPI backend. This is not great, but at least avoids regressions and the fix should be small enough to allow backporting. As a side-effect this also works around a shutdown problem on the Asus C201. For reasons unknown that skips calling the prepare handler and directly calls the final shutdown handler. Fixes: 4fec8a5a85c49 ("mfd: rk808: Convert to device managed resources") Cc: stable(a)vger.kernel.org Reported-by: Urja <urja(a)urja.dev> Signed-off-by: Sebastian Reichel <sebastian.reichel(a)collabora.com> --- drivers/mfd/rk8xx-core.c | 15 +++++++++++++-- drivers/mfd/rk8xx-i2c.c | 2 +- drivers/mfd/rk8xx-spi.c | 2 +- include/linux/mfd/rk808.h | 2 +- 4 files changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/mfd/rk8xx-core.c b/drivers/mfd/rk8xx-core.c index 5eda3c0dbbdf..757ef8181328 100644 --- a/drivers/mfd/rk8xx-core.c +++ b/drivers/mfd/rk8xx-core.c @@ -692,10 +692,11 @@ void rk8xx_shutdown(struct device *dev) } EXPORT_SYMBOL_GPL(rk8xx_shutdown); -int rk8xx_probe(struct device *dev, int variant, unsigned int irq, struct regmap *regmap) +int rk8xx_probe(struct device *dev, int variant, unsigned int irq, struct regmap *regmap, bool is_spi) { struct rk808 *rk808; const struct rk808_reg_data *pre_init_reg; + enum sys_off_mode pwr_off_mode = SYS_OFF_MODE_POWER_OFF; const struct mfd_cell *cells; int dual_support = 0; int nr_pre_init_regs; @@ -785,10 +786,20 @@ int rk8xx_probe(struct device *dev, int variant, unsigned int irq, struct regmap if (ret) return dev_err_probe(dev, ret, "failed to add MFD devices\n"); + /* + * Currently the Rockchip SPI driver always sleeps when doing SPI + * transfers. This is not allowed in the SYS_OFF_MODE_POWER_OFF + * handler, so we are using the prepare handler as a workaround. + * This should be removed once the Rockchip SPI driver has been + * adapted. + */ + if (is_spi) + pwr_off_mode = SYS_OFF_MODE_POWER_OFF_PREPARE; + if (device_property_read_bool(dev, "rockchip,system-power-controller") || device_property_read_bool(dev, "system-power-controller")) { ret = devm_register_sys_off_handler(dev, - SYS_OFF_MODE_POWER_OFF_PREPARE, SYS_OFF_PRIO_HIGH, + pwr_off_mode, SYS_OFF_PRIO_HIGH, &rk808_power_off, rk808); if (ret) return dev_err_probe(dev, ret, diff --git a/drivers/mfd/rk8xx-i2c.c b/drivers/mfd/rk8xx-i2c.c index 69a6b297d723..a2029decd654 100644 --- a/drivers/mfd/rk8xx-i2c.c +++ b/drivers/mfd/rk8xx-i2c.c @@ -189,7 +189,7 @@ static int rk8xx_i2c_probe(struct i2c_client *client) return dev_err_probe(&client->dev, PTR_ERR(regmap), "regmap initialization failed\n"); - return rk8xx_probe(&client->dev, data->variant, client->irq, regmap); + return rk8xx_probe(&client->dev, data->variant, client->irq, regmap, false); } static void rk8xx_i2c_shutdown(struct i2c_client *client) diff --git a/drivers/mfd/rk8xx-spi.c b/drivers/mfd/rk8xx-spi.c index 3405fb82ff9f..20f9428f94bb 100644 --- a/drivers/mfd/rk8xx-spi.c +++ b/drivers/mfd/rk8xx-spi.c @@ -94,7 +94,7 @@ static int rk8xx_spi_probe(struct spi_device *spi) return dev_err_probe(&spi->dev, PTR_ERR(regmap), "Failed to init regmap\n"); - return rk8xx_probe(&spi->dev, RK806_ID, spi->irq, regmap); + return rk8xx_probe(&spi->dev, RK806_ID, spi->irq, regmap, true); } static const struct of_device_id rk8xx_spi_of_match[] = { diff --git a/include/linux/mfd/rk808.h b/include/linux/mfd/rk808.h index 69cbea78b430..be15b84cff9e 100644 --- a/include/linux/mfd/rk808.h +++ b/include/linux/mfd/rk808.h @@ -1349,7 +1349,7 @@ struct rk808 { }; void rk8xx_shutdown(struct device *dev); -int rk8xx_probe(struct device *dev, int variant, unsigned int irq, struct regmap *regmap); +int rk8xx_probe(struct device *dev, int variant, unsigned int irq, struct regmap *regmap, bool is_spi); int rk8xx_suspend(struct device *dev); int rk8xx_resume(struct device *dev); -- 2.43.0 [View Less]

2 weeks, 2 days

8
12
0 0

[PATCH] drm: Remove redundant statement in drm_crtc_helper_set_mode()

by Huacai Chen

Commit dbbfaf5f2641a ("drm: Remove bridge support from legacy helpers") removes the drm_bridge_mode_fixup() call in drm_crtc_helper_set_mode(), which makes the subsequent "encoder_funcs = encoder->helper_private" be redundant, so remove it. Cc: stable(a)vger.kernel.org Fixes: dbbfaf5f2641a ("drm: Remove bridge support from legacy helpers") Signed-off-by: Huacai Chen <chenhuacai(a)loongson.cn> --- drivers/gpu/drm/drm_crtc_helper.c | 1 - 1 file changed, 1 deletion(-) diff --git a/… [View More]

2 weeks, 3 days

3
5
0 0

[PATCH v2] sched/fair: Fix integer underflow

by Pierre Gondois

(struct sg_lb_stats).idle_cpus is of type 'unsigned int'. (local->idle_cpus - busiest->idle_cpus) can underflow to UINT_MAX for instance, and max_t(long, 0, UINT_MAX) will output UINT_MAX. Use lsub_positive() instead of max_t(). Fixes: 16b0a7a1a0af ("sched/fair: Ensure tasks spreading in LLC during LB") cc: stable(a)vger.kernel.org Signed-off-by: Pierre Gondois <pierre.gondois(a)arm.com> Reviewed-by: Vincent Guittot <vincent.guittot(a)linaro.org> --- kernel/sched/fair.c | 4 … [View More]

2 weeks, 3 days

2
2
0 0

[PATCH 6.1.y 6.6.y 0/3] mm/filemap: fix page cache corruption with large folios

by Kairui Song

From: Kairui Song <kasong(a)tencent.com> This series fixes the page cache corruption issue reported by Christian Theune [1]. The issue was reported affects kernels back to 5.19. Current maintained effected branches includes 6.1 and 6.6 and the fix was included in 6.10 already. This series can be applied for both 6.1 and 6.6. Patch 3/3 is the fixing patch. It was initially submitted and merge as an optimization but found to have fixed the corruption by handling race correctly. Patch 1/… [View More]

2 weeks, 5 days

6
14
0 0

FAILED: patch "[PATCH] block: fix missing dispatching request when queue is started" 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 2003ee8a9aa14d766b06088156978d53c2e9be3d # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024120323-snowiness-subway-3844@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2003ee8a9aa14d766b06088156978d53c2e9be3d Mon Sep 17 00:00:00 2001 From: Muchun Song <muchun.song(a)linux.dev> Date: Mon, 14 Oct 2024 17:29:32 +0800 Subject: [PATCH] block: fix missing dispatching request when queue is started or unquiesced Supposing the following scenario with a virtio_blk driver. CPU0 CPU1 CPU2 blk_mq_try_issue_directly() __blk_mq_issue_directly() q->mq_ops->queue_rq() virtio_queue_rq() blk_mq_stop_hw_queue() virtblk_done() blk_mq_try_issue_directly() if (blk_mq_hctx_stopped()) blk_mq_request_bypass_insert() blk_mq_run_hw_queue() blk_mq_run_hw_queue() blk_mq_run_hw_queue() blk_mq_insert_request() return After CPU0 has marked the queue as stopped, CPU1 will see the queue is stopped. But before CPU1 puts the request on the dispatch list, CPU2 receives the interrupt of completion of request, so it will run the hardware queue and marks the queue as non-stopped. Meanwhile, CPU1 also runs the same hardware queue. After both CPU1 and CPU2 complete blk_mq_run_hw_queue(), CPU1 just puts the request to the same hardware queue and returns. It misses dispatching a request. Fix it by running the hardware queue explicitly. And blk_mq_request_issue_directly() should handle a similar situation. Fix it as well. Fixes: d964f04a8fde ("blk-mq: fix direct issue") Cc: stable(a)vger.kernel.org Cc: Muchun Song <muchun.song(a)linux.dev> Signed-off-by: Muchun Song <songmuchun(a)bytedance.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> Link: https://lore.kernel.org/r/20241014092934.53630-2-songmuchun@bytedance.com Signed-off-by: Jens Axboe <axboe(a)kernel.dk> diff --git a/block/blk-mq.c b/block/blk-mq.c index 7d05a56e3639..5deb9dffca0a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2647,6 +2647,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { blk_mq_insert_request(rq, 0); + blk_mq_run_hw_queue(hctx, false); return; } @@ -2677,6 +2678,7 @@ static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { blk_mq_insert_request(rq, 0); + blk_mq_run_hw_queue(hctx, false); return BLK_STS_OK; } [View Less]

3 weeks, 5 days

4
5
0 0

FAILED: patch "[PATCH] block: fix ordering between checking QUEUE_FLAG_QUIESCED" 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 6bda857bcbb86fb9d0e54fbef93a093d51172acc # <… [View More]resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024120342-monsoon-wildcat-d0a1@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 6bda857bcbb86fb9d0e54fbef93a093d51172acc Mon Sep 17 00:00:00 2001 From: Muchun Song <muchun.song(a)linux.dev> Date: Mon, 14 Oct 2024 17:29:33 +0800 Subject: [PATCH] block: fix ordering between checking QUEUE_FLAG_QUIESCED request adding Supposing the following scenario. CPU0 CPU1 blk_mq_insert_request() 1) store blk_mq_unquiesce_queue() blk_queue_flag_clear() 3) store blk_mq_run_hw_queues() blk_mq_run_hw_queue() if (!blk_mq_hctx_has_pending()) 4) load return blk_mq_run_hw_queue() if (blk_queue_quiesced()) 2) load return blk_mq_sched_dispatch_requests() The full memory barrier should be inserted between 1) and 2), as well as between 3) and 4) to make sure that either CPU0 sees QUEUE_FLAG_QUIESCED is cleared or CPU1 sees dispatch list or setting of bitmap of software queue. Otherwise, either CPU will not rerun the hardware queue causing starvation. So the first solution is to 1) add a pair of memory barrier to fix the problem, another solution is to 2) use hctx->queue->queue_lock to synchronize QUEUE_FLAG_QUIESCED. Here, we chose 2) to fix it since memory barrier is not easy to be maintained. Fixes: f4560ffe8cec ("blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue") Cc: stable(a)vger.kernel.org Cc: Muchun Song <muchun.song(a)linux.dev> Signed-off-by: Muchun Song <songmuchun(a)bytedance.com> Reviewed-by: Ming Lei <ming.lei(a)redhat.com> Link: https://lore.kernel.org/r/20241014092934.53630-3-songmuchun@bytedance.com Signed-off-by: Jens Axboe <axboe(a)kernel.dk> diff --git a/block/blk-mq.c b/block/blk-mq.c index 5deb9dffca0a..bb4ee2380dce 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2227,6 +2227,24 @@ void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) } EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); +static inline bool blk_mq_hw_queue_need_run(struct blk_mq_hw_ctx *hctx) +{ + bool need_run; + + /* + * When queue is quiesced, we may be switching io scheduler, or + * updating nr_hw_queues, or other things, and we can't run queue + * any more, even blk_mq_hctx_has_pending() can't be called safely. + * + * And queue will be rerun in blk_mq_unquiesce_queue() if it is + * quiesced. + */ + __blk_mq_run_dispatch_ops(hctx->queue, false, + need_run = !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx)); + return need_run; +} + /** * blk_mq_run_hw_queue - Start to run a hardware queue. * @hctx: Pointer to the hardware queue to run. @@ -2247,20 +2265,23 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING); - /* - * When queue is quiesced, we may be switching io scheduler, or - * updating nr_hw_queues, or other things, and we can't run queue - * any more, even __blk_mq_hctx_has_pending() can't be called safely. - * - * And queue will be rerun in blk_mq_unquiesce_queue() if it is - * quiesced. - */ - __blk_mq_run_dispatch_ops(hctx->queue, false, - need_run = !blk_queue_quiesced(hctx->queue) && - blk_mq_hctx_has_pending(hctx)); + need_run = blk_mq_hw_queue_need_run(hctx); + if (!need_run) { + unsigned long flags; - if (!need_run) - return; + /* + * Synchronize with blk_mq_unquiesce_queue(), because we check + * if hw queue is quiesced locklessly above, we need the use + * ->queue_lock to make sure we see the up-to-date status to + * not miss rerunning the hw queue. + */ + spin_lock_irqsave(&hctx->queue->queue_lock, flags); + need_run = blk_mq_hw_queue_need_run(hctx); + spin_unlock_irqrestore(&hctx->queue->queue_lock, flags); + + if (!need_run) + return; + } if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { blk_mq_delay_run_hw_queue(hctx, 0); [View Less]

3 weeks, 5 days

4
5
0 0

[REGRESSION][BISECTED] Commit 60e3318e3e900 in stable/linux-6.1.y breaks cifs client failover to another server in DFS namespace

by Andrew Paniakin

Commit 60e3318e3e900 ("cifs: use fs_context for automounts") was released in v6.1.54 and broke the failover when one of the servers inside DFS becomes unavailable. We reproduced the problem on the EC2 instances of different types. Reverting aforementioned commint on top of the latest stable verison v6.1.94 helps to resolve the problem. Earliest working version is v6.2-rc1. There were two big merges of CIFS fixes: [1] and [2]. We would like to ask for the help to investigate this problem and if … [View More]some of those patches need to be backported. Also, is it safe to just revert problematic commit until proper fixes/backports will be available? We will help to do testing and confirm if fix works, but let me also list the steps we used to reproduce the problem if it will help to identify the problem: 1. Create Active Directory domain eg. 'corp.fsxtest.local' in AWS Directory Service with: - three AWS FSX file systems filesystem1..filesystem3 - three Windows servers; They have DFS installed as per https://learn.microsoft.com/en-us/windows-server/storage/dfs-namespaces/dfs…: - dfs-srv1: EC2AMAZ-2EGTM59 - dfs-srv2: EC2AMAZ-1N36PRD - dfs-srv3: EC2AMAZ-0PAUH2U 2. Create DFS namespace eg. 'dfs-namespace' in Windows server 2008 mode and three folders targets in it: - referral-a mapped to filesystem1.corp.local - referral-b mapped to filesystem2.corp.local - referral-c mapped to filesystem3.corp.local - local folders dfs-srv1..dfs-srv3 in C:\DFSRoots\dfs-namespace of every Windows server. This helps to quickly define underlying server when DFS is mounted. 3. Enabled cifs debug logs: ``` echo 'module cifs +p' > /sys/kernel/debug/dynamic_debug/control echo 'file fs/cifs/* +p' > /sys/kernel/debug/dynamic_debug/control echo 7 > /proc/fs/cifs/cifsFYI ``` 4. Mount DFS namespace on Amazon Linux 2023 instance running any vanilla kernel v6.1.54+: ``` dmesg -c &>/dev/null cd /mnt mount -t cifs -o cred=/mnt/creds,echo_interval=5 \ //corp.fsxtest.local/dfs-namespace \ ./dfs-namespace ``` 5. List DFS root, it's also required to avoid recursive mounts that happen during regular 'ls' run: ``` sh -c 'ls dfs-namespace' dfs-srv2 referral-a referral-b ``` The DFS server is EC2AMAZ-1N36PRD, it's also listed in mount: ``` [root@ip-172-31-2-82 mnt]# mount | grep dfs //corp.fsxtest.local/dfs-namespace on /mnt/dfs-namespace type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.11.26,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1) //EC2AMAZ-1N36PRD.corp.fsxtest.local/dfs-namespace/referral-a on /mnt/dfs-namespace/referral-a type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.12.80,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1) ``` List files in first folder: ``` sh -c 'ls dfs-namespace/referral-a' filea.txt.txt ``` 6. Shutdown DFS server-2. List DFS root again, server changed from dfs-srv2 to dfs-srv1 EC2AMAZ-2EGTM59: ``` sh -c 'ls dfs-namespace' dfs-srv1 referral-a referral-b ``` 7. Try to list files in another folder, this causes ls to fail with error: ``` sh -c 'ls dfs-namespace/referral-b' ls: cannot access 'dfs-namespace/referral-b': No route to host``` Sometimes it's also 'Operation now in progress' error. mount shows the same output: ``` //corp.fsxtest.local/dfs-namespace on /mnt/dfs-namespace type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.11.26,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1) //EC2AMAZ-1N36PRD.corp.fsxtest.local/dfs-namespace/referral-a on /mnt/dfs-namespace/referral-a type cifs (rw,relatime,vers=3.1.1,cache=strict,username=Admin,domain=corp.fsxtest.local,uid=0,noforceuid,gid=0,noforcegid,addr=172.31.12.80,file_mode=0755,dir_mode=0755,soft,nounix,mapposix,rsize=4194304,wsize=4194304,bsize=1048576,echo_interval=5,actimeo=1,closetimeo=1) ``` I also attached kernel debug logs from this test. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… Reported-by: Andrei Paniakin <apanyaki(a)amazon.com> Bisected-by: Simba Bonga <simbarb(a)amazon.com> --- #regzbot introduced: v6.1.54..v6.2-rc1 [View Less]

3 weeks, 6 days

3
11
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-stable-mirror December 2024