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4 months

[PATCH 0/3] hwmon: (sht21) Add devicetree support

by Kurt Borja

Hi all, The sht21 driver actually supports all i2c sht2x chips so add support for those names and additionally add DT support. Tested for sht20 and verified against the datasheet for sht25. Thanks! Signed-off-by: Kurt Borja <kuurtb(a)gmail.com> --- Kurt Borja (3): hwmon: (sht21) Add support for all sht2x chips hwmon: (sht21) Add devicetree support dt-bindings: trivial-devices: Add sht2x sensors Documentation/devicetree/bindings/trivial-devices.yaml | 1 + Documentation/hwmon/sht21.rst | 11 +++++++++++ drivers/hwmon/sht21.c | 13 ++++++++++++- 3 files changed, 24 insertions(+), 1 deletion(-) --- base-commit: b236920731dd90c3fba8c227aa0c4dee5351a639 change-id: 20250907-sht2x-9b96125a0cf5 -- ~ Kurt

4 months

FAILED: patch "[PATCH] mm/rmap: reject hugetlb folios in" 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 bc3fe6805cf09a25a086573a17d40e525208c5d8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025041752-tightwad-catwalk-8586@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From bc3fe6805cf09a25a086573a17d40e525208c5d8 Mon Sep 17 00:00:00 2001 From: David Hildenbrand <david(a)redhat.com> Date: Mon, 10 Feb 2025 20:37:44 +0100 Subject: [PATCH] mm/rmap: reject hugetlb folios in folio_make_device_exclusive() Even though FOLL_SPLIT_PMD on hugetlb now always fails with -EOPNOTSUPP, let's add a safety net in case FOLL_SPLIT_PMD usage would ever be reworked. In particular, before commit 9cb28da54643 ("mm/gup: handle hugetlb in the generic follow_page_mask code"), GUP(FOLL_SPLIT_PMD) would just have returned a page. In particular, hugetlb folios that are not PMD-sized would never have been prone to FOLL_SPLIT_PMD. hugetlb folios can be anonymous, and page_make_device_exclusive_one() is not really prepared for handling them at all. So let's spell that out. Link: https://lkml.kernel.org/r/20250210193801.781278-3-david@redhat.com Fixes: b756a3b5e7ea ("mm: device exclusive memory access") Signed-off-by: David Hildenbrand <david(a)redhat.com> Reviewed-by: Alistair Popple <apopple(a)nvidia.com> Tested-by: Alistair Popple <apopple(a)nvidia.com> Cc: Alex Shi <alexs(a)kernel.org> Cc: Danilo Krummrich <dakr(a)kernel.org> Cc: Dave Airlie <airlied(a)gmail.com> Cc: Jann Horn <jannh(a)google.com> Cc: Jason Gunthorpe <jgg(a)nvidia.com> Cc: Jerome Glisse <jglisse(a)redhat.com> Cc: John Hubbard <jhubbard(a)nvidia.com> Cc: Jonathan Corbet <corbet(a)lwn.net> Cc: Karol Herbst <kherbst(a)redhat.com> Cc: Liam Howlett <liam.howlett(a)oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Lyude <lyude(a)redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat(a)kernel.org> Cc: Oleg Nesterov <oleg(a)redhat.com> Cc: Pasha Tatashin <pasha.tatashin(a)soleen.com> Cc: Peter Xu <peterx(a)redhat.com> Cc: Peter Zijlstra (Intel) <peterz(a)infradead.org> Cc: SeongJae Park <sj(a)kernel.org> Cc: Simona Vetter <simona.vetter(a)ffwll.ch> Cc: Vlastimil Babka <vbabka(a)suse.cz> Cc: Yanteng Si <si.yanteng(a)linux.dev> Cc: Barry Song <v-songbaohua(a)oppo.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/rmap.c b/mm/rmap.c index c6c4d4ea29a7..17fbfa61f7ef 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2499,7 +2499,7 @@ static bool folio_make_device_exclusive(struct folio *folio, * Restrict to anonymous folios for now to avoid potential writeback * issues. */ - if (!folio_test_anon(folio)) + if (!folio_test_anon(folio) || folio_test_hugetlb(folio)) return false; rmap_walk(folio, &rwc);

4 months

Re: [PATCH net v4] netrom: linearize and validate lengths in nr_rx_frame()

by Jiri Kosina

On Sun, 7 Sep 2025, Bernard Pidoux wrote: > While applying netrom PATCH net v4 > patch says that > it is malformed on line 12. > > However I cannot see any reason. There is a superfluous leading space on each line of the diff. (wasn't the case with the previous patches, v4 is the first one to have this). -- Jiri Kosina SUSE Labs

4 months

FAILED: patch "[PATCH] mm: slub: avoid wake up kswapd in set_track_prepare" 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 850470a8413a8a78e772c4f6bd9fe81ec6bd5b0f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025090635-affluent-reputable-419b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 850470a8413a8a78e772c4f6bd9fe81ec6bd5b0f Mon Sep 17 00:00:00 2001 From: yangshiguang <yangshiguang(a)xiaomi.com> Date: Sat, 30 Aug 2025 10:09:46 +0800 Subject: [PATCH] mm: slub: avoid wake up kswapd in set_track_prepare set_track_prepare() can incur lock recursion. The issue is that it is called from hrtimer_start_range_ns holding the per_cpu(hrtimer_bases)[n].lock, but when enabled CONFIG_DEBUG_OBJECTS_TIMERS, may wake up kswapd in set_track_prepare, and try to hold the per_cpu(hrtimer_bases)[n].lock. Avoid deadlock caused by implicitly waking up kswapd by passing in allocation flags, which do not contain __GFP_KSWAPD_RECLAIM in the debug_objects_fill_pool() case. Inside stack depot they are processed by gfp_nested_mask(). Since ___slab_alloc() has preemption disabled, we mask out __GFP_DIRECT_RECLAIM from the flags there. The oops looks something like: BUG: spinlock recursion on CPU#3, swapper/3/0 lock: 0xffffff8a4bf29c80, .magic: dead4ead, .owner: swapper/3/0, .owner_cpu: 3 Hardware name: Qualcomm Technologies, Inc. Popsicle based on SM8850 (DT) Call trace: spin_bug+0x0 _raw_spin_lock_irqsave+0x80 hrtimer_try_to_cancel+0x94 task_contending+0x10c enqueue_dl_entity+0x2a4 dl_server_start+0x74 enqueue_task_fair+0x568 enqueue_task+0xac do_activate_task+0x14c ttwu_do_activate+0xcc try_to_wake_up+0x6c8 default_wake_function+0x20 autoremove_wake_function+0x1c __wake_up+0xac wakeup_kswapd+0x19c wake_all_kswapds+0x78 __alloc_pages_slowpath+0x1ac __alloc_pages_noprof+0x298 stack_depot_save_flags+0x6b0 stack_depot_save+0x14 set_track_prepare+0x5c ___slab_alloc+0xccc __kmalloc_cache_noprof+0x470 __set_page_owner+0x2bc post_alloc_hook[jt]+0x1b8 prep_new_page+0x28 get_page_from_freelist+0x1edc __alloc_pages_noprof+0x13c alloc_slab_page+0x244 allocate_slab+0x7c ___slab_alloc+0x8e8 kmem_cache_alloc_noprof+0x450 debug_objects_fill_pool+0x22c debug_object_activate+0x40 enqueue_hrtimer[jt]+0xdc hrtimer_start_range_ns+0x5f8 ... Signed-off-by: yangshiguang <yangshiguang(a)xiaomi.com> Fixes: 5cf909c553e9 ("mm/slub: use stackdepot to save stack trace in objects") Cc: stable(a)vger.kernel.org Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> diff --git a/mm/slub.c b/mm/slub.c index 1787e4d51e48..d257141896c9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -962,19 +962,19 @@ static struct track *get_track(struct kmem_cache *s, void *object, } #ifdef CONFIG_STACKDEPOT -static noinline depot_stack_handle_t set_track_prepare(void) +static noinline depot_stack_handle_t set_track_prepare(gfp_t gfp_flags) { depot_stack_handle_t handle; unsigned long entries[TRACK_ADDRS_COUNT]; unsigned int nr_entries; nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); - handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); + handle = stack_depot_save(entries, nr_entries, gfp_flags); return handle; } #else -static inline depot_stack_handle_t set_track_prepare(void) +static inline depot_stack_handle_t set_track_prepare(gfp_t gfp_flags) { return 0; } @@ -996,9 +996,9 @@ static void set_track_update(struct kmem_cache *s, void *object, } static __always_inline void set_track(struct kmem_cache *s, void *object, - enum track_item alloc, unsigned long addr) + enum track_item alloc, unsigned long addr, gfp_t gfp_flags) { - depot_stack_handle_t handle = set_track_prepare(); + depot_stack_handle_t handle = set_track_prepare(gfp_flags); set_track_update(s, object, alloc, addr, handle); } @@ -1926,9 +1926,9 @@ static inline bool free_debug_processing(struct kmem_cache *s, static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {} static inline int check_object(struct kmem_cache *s, struct slab *slab, void *object, u8 val) { return 1; } -static inline depot_stack_handle_t set_track_prepare(void) { return 0; } +static inline depot_stack_handle_t set_track_prepare(gfp_t gfp_flags) { return 0; } static inline void set_track(struct kmem_cache *s, void *object, - enum track_item alloc, unsigned long addr) {} + enum track_item alloc, unsigned long addr, gfp_t gfp_flags) {} static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab) {} static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, @@ -3881,9 +3881,14 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, * For debug caches here we had to go through * alloc_single_from_partial() so just store the * tracking info and return the object. + * + * Due to disabled preemption we need to disallow + * blocking. The flags are further adjusted by + * gfp_nested_mask() in stack_depot itself. */ if (s->flags & SLAB_STORE_USER) - set_track(s, freelist, TRACK_ALLOC, addr); + set_track(s, freelist, TRACK_ALLOC, addr, + gfpflags & ~(__GFP_DIRECT_RECLAIM)); return freelist; } @@ -3915,7 +3920,8 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, goto new_objects; if (s->flags & SLAB_STORE_USER) - set_track(s, freelist, TRACK_ALLOC, addr); + set_track(s, freelist, TRACK_ALLOC, addr, + gfpflags & ~(__GFP_DIRECT_RECLAIM)); return freelist; } @@ -4426,8 +4432,12 @@ static noinline void free_to_partial_list( unsigned long flags; depot_stack_handle_t handle = 0; + /* + * We cannot use GFP_NOWAIT as there are callsites where waking up + * kswapd could deadlock + */ if (s->flags & SLAB_STORE_USER) - handle = set_track_prepare(); + handle = set_track_prepare(__GFP_NOWARN); spin_lock_irqsave(&n->list_lock, flags);

4 months

FAILED: patch "[PATCH] cifs: fix integer overflow in match_server()" 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 2510859475d7f46ed7940db0853f3342bf1b65ee # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025041700-afar-darkness-e9b8@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2510859475d7f46ed7940db0853f3342bf1b65ee Mon Sep 17 00:00:00 2001 From: Roman Smirnov <r.smirnov(a)omp.ru> Date: Mon, 31 Mar 2025 11:22:49 +0300 Subject: [PATCH] cifs: fix integer overflow in match_server() The echo_interval is not limited in any way during mounting, which makes it possible to write a large number to it. This can cause an overflow when multiplying ctx->echo_interval by HZ in match_server(). Add constraints for echo_interval to smb3_fs_context_parse_param(). Found by Linux Verification Center (linuxtesting.org) with Svace. Fixes: adfeb3e00e8e1 ("cifs: Make echo interval tunable") Cc: stable(a)vger.kernel.org Signed-off-by: Roman Smirnov <r.smirnov(a)omp.ru> Signed-off-by: Steve French <stfrench(a)microsoft.com> diff --git a/fs/smb/client/fs_context.c b/fs/smb/client/fs_context.c index bdb762d398af..9c3ded0cf006 100644 --- a/fs/smb/client/fs_context.c +++ b/fs/smb/client/fs_context.c @@ -1383,6 +1383,11 @@ static int smb3_fs_context_parse_param(struct fs_context *fc, ctx->closetimeo = HZ * result.uint_32; break; case Opt_echo_interval: + if (result.uint_32 < SMB_ECHO_INTERVAL_MIN || + result.uint_32 > SMB_ECHO_INTERVAL_MAX) { + cifs_errorf(fc, "echo interval is out of bounds\n"); + goto cifs_parse_mount_err; + } ctx->echo_interval = result.uint_32; break; case Opt_snapshot:

4 months

FAILED: patch "[PATCH] clk: qcom: gdsc: Set retain_ff before moving to HW CTRL" 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 25708f73ff171bb4171950c9f4be5aa8504b8459 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025041713-sterility-resample-9288@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 25708f73ff171bb4171950c9f4be5aa8504b8459 Mon Sep 17 00:00:00 2001 From: Taniya Das <quic_tdas(a)quicinc.com> Date: Fri, 14 Feb 2025 09:56:59 +0530 Subject: [PATCH] clk: qcom: gdsc: Set retain_ff before moving to HW CTRL Enable the retain_ff_enable bit of GDSCR only if the GDSC is already ON. Once the GDSCR moves to HW control, SW no longer can determine the state of the GDSCR and setting the retain_ff bit could destroy all the register contents we intended to save. Therefore, move the retain_ff configuration before switching the GDSC to HW trigger mode. Cc: stable(a)vger.kernel.org Fixes: 173722995cdb ("clk: qcom: gdsc: Add support to enable retention of GSDCR") Signed-off-by: Taniya Das <quic_tdas(a)quicinc.com> Reviewed-by: Imran Shaik <quic_imrashai(a)quicinc.com> Tested-by: Imran Shaik <quic_imrashai(a)quicinc.com> # on QCS8300 Link: https://lore.kernel.org/r/20250214-gdsc_fixes-v1-1-73e56d68a80f@quicinc.com Signed-off-by: Bjorn Andersson <andersson(a)kernel.org> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c index 7687661491f1..f3f95f4d9313 100644 --- a/drivers/clk/qcom/gdsc.c +++ b/drivers/clk/qcom/gdsc.c @@ -292,6 +292,9 @@ static int gdsc_enable(struct generic_pm_domain *domain) */ udelay(1); + if (sc->flags & RETAIN_FF_ENABLE) + gdsc_retain_ff_on(sc); + /* Turn on HW trigger mode if supported */ if (sc->flags & HW_CTRL) { ret = gdsc_hwctrl(sc, true); @@ -308,9 +311,6 @@ static int gdsc_enable(struct generic_pm_domain *domain) udelay(1); } - if (sc->flags & RETAIN_FF_ENABLE) - gdsc_retain_ff_on(sc); - return 0; } @@ -457,13 +457,6 @@ static int gdsc_init(struct gdsc *sc) goto err_disable_supply; } - /* Turn on HW trigger mode if supported */ - if (sc->flags & HW_CTRL) { - ret = gdsc_hwctrl(sc, true); - if (ret < 0) - goto err_disable_supply; - } - /* * Make sure the retain bit is set if the GDSC is already on, * otherwise we end up turning off the GDSC and destroying all @@ -471,6 +464,14 @@ static int gdsc_init(struct gdsc *sc) */ if (sc->flags & RETAIN_FF_ENABLE) gdsc_retain_ff_on(sc); + + /* Turn on HW trigger mode if supported */ + if (sc->flags & HW_CTRL) { + ret = gdsc_hwctrl(sc, true); + if (ret < 0) + goto err_disable_supply; + } + } else if (sc->flags & ALWAYS_ON) { /* If ALWAYS_ON GDSCs are not ON, turn them ON */ gdsc_enable(&sc->pd);

4 months

FAILED: patch "[PATCH] cifs: fix integer overflow in match_server()" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

4 months

FAILED: patch "[PATCH] clk: qcom: gdsc: Set retain_ff before moving to HW CTRL" 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 25708f73ff171bb4171950c9f4be5aa8504b8459 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025041712-antibody-octane-7c74@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 25708f73ff171bb4171950c9f4be5aa8504b8459 Mon Sep 17 00:00:00 2001 From: Taniya Das <quic_tdas(a)quicinc.com> Date: Fri, 14 Feb 2025 09:56:59 +0530 Subject: [PATCH] clk: qcom: gdsc: Set retain_ff before moving to HW CTRL Enable the retain_ff_enable bit of GDSCR only if the GDSC is already ON. Once the GDSCR moves to HW control, SW no longer can determine the state of the GDSCR and setting the retain_ff bit could destroy all the register contents we intended to save. Therefore, move the retain_ff configuration before switching the GDSC to HW trigger mode. Cc: stable(a)vger.kernel.org Fixes: 173722995cdb ("clk: qcom: gdsc: Add support to enable retention of GSDCR") Signed-off-by: Taniya Das <quic_tdas(a)quicinc.com> Reviewed-by: Imran Shaik <quic_imrashai(a)quicinc.com> Tested-by: Imran Shaik <quic_imrashai(a)quicinc.com> # on QCS8300 Link: https://lore.kernel.org/r/20250214-gdsc_fixes-v1-1-73e56d68a80f@quicinc.com Signed-off-by: Bjorn Andersson <andersson(a)kernel.org> diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c index 7687661491f1..f3f95f4d9313 100644 --- a/drivers/clk/qcom/gdsc.c +++ b/drivers/clk/qcom/gdsc.c @@ -292,6 +292,9 @@ static int gdsc_enable(struct generic_pm_domain *domain) */ udelay(1); + if (sc->flags & RETAIN_FF_ENABLE) + gdsc_retain_ff_on(sc); + /* Turn on HW trigger mode if supported */ if (sc->flags & HW_CTRL) { ret = gdsc_hwctrl(sc, true); @@ -308,9 +311,6 @@ static int gdsc_enable(struct generic_pm_domain *domain) udelay(1); } - if (sc->flags & RETAIN_FF_ENABLE) - gdsc_retain_ff_on(sc); - return 0; } @@ -457,13 +457,6 @@ static int gdsc_init(struct gdsc *sc) goto err_disable_supply; } - /* Turn on HW trigger mode if supported */ - if (sc->flags & HW_CTRL) { - ret = gdsc_hwctrl(sc, true); - if (ret < 0) - goto err_disable_supply; - } - /* * Make sure the retain bit is set if the GDSC is already on, * otherwise we end up turning off the GDSC and destroying all @@ -471,6 +464,14 @@ static int gdsc_init(struct gdsc *sc) */ if (sc->flags & RETAIN_FF_ENABLE) gdsc_retain_ff_on(sc); + + /* Turn on HW trigger mode if supported */ + if (sc->flags & HW_CTRL) { + ret = gdsc_hwctrl(sc, true); + if (ret < 0) + goto err_disable_supply; + } + } else if (sc->flags & ALWAYS_ON) { /* If ALWAYS_ON GDSCs are not ON, turn them ON */ gdsc_enable(&sc->pd);

4 months

FAILED: patch "[PATCH] mm: slub: avoid wake up kswapd in set_track_prepare" 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 850470a8413a8a78e772c4f6bd9fe81ec6bd5b0f # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025090634-predator-composite-c799@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 850470a8413a8a78e772c4f6bd9fe81ec6bd5b0f Mon Sep 17 00:00:00 2001 From: yangshiguang <yangshiguang(a)xiaomi.com> Date: Sat, 30 Aug 2025 10:09:46 +0800 Subject: [PATCH] mm: slub: avoid wake up kswapd in set_track_prepare set_track_prepare() can incur lock recursion. The issue is that it is called from hrtimer_start_range_ns holding the per_cpu(hrtimer_bases)[n].lock, but when enabled CONFIG_DEBUG_OBJECTS_TIMERS, may wake up kswapd in set_track_prepare, and try to hold the per_cpu(hrtimer_bases)[n].lock. Avoid deadlock caused by implicitly waking up kswapd by passing in allocation flags, which do not contain __GFP_KSWAPD_RECLAIM in the debug_objects_fill_pool() case. Inside stack depot they are processed by gfp_nested_mask(). Since ___slab_alloc() has preemption disabled, we mask out __GFP_DIRECT_RECLAIM from the flags there. The oops looks something like: BUG: spinlock recursion on CPU#3, swapper/3/0 lock: 0xffffff8a4bf29c80, .magic: dead4ead, .owner: swapper/3/0, .owner_cpu: 3 Hardware name: Qualcomm Technologies, Inc. Popsicle based on SM8850 (DT) Call trace: spin_bug+0x0 _raw_spin_lock_irqsave+0x80 hrtimer_try_to_cancel+0x94 task_contending+0x10c enqueue_dl_entity+0x2a4 dl_server_start+0x74 enqueue_task_fair+0x568 enqueue_task+0xac do_activate_task+0x14c ttwu_do_activate+0xcc try_to_wake_up+0x6c8 default_wake_function+0x20 autoremove_wake_function+0x1c __wake_up+0xac wakeup_kswapd+0x19c wake_all_kswapds+0x78 __alloc_pages_slowpath+0x1ac __alloc_pages_noprof+0x298 stack_depot_save_flags+0x6b0 stack_depot_save+0x14 set_track_prepare+0x5c ___slab_alloc+0xccc __kmalloc_cache_noprof+0x470 __set_page_owner+0x2bc post_alloc_hook[jt]+0x1b8 prep_new_page+0x28 get_page_from_freelist+0x1edc __alloc_pages_noprof+0x13c alloc_slab_page+0x244 allocate_slab+0x7c ___slab_alloc+0x8e8 kmem_cache_alloc_noprof+0x450 debug_objects_fill_pool+0x22c debug_object_activate+0x40 enqueue_hrtimer[jt]+0xdc hrtimer_start_range_ns+0x5f8 ... Signed-off-by: yangshiguang <yangshiguang(a)xiaomi.com> Fixes: 5cf909c553e9 ("mm/slub: use stackdepot to save stack trace in objects") Cc: stable(a)vger.kernel.org Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz> diff --git a/mm/slub.c b/mm/slub.c index 1787e4d51e48..d257141896c9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -962,19 +962,19 @@ static struct track *get_track(struct kmem_cache *s, void *object, } #ifdef CONFIG_STACKDEPOT -static noinline depot_stack_handle_t set_track_prepare(void) +static noinline depot_stack_handle_t set_track_prepare(gfp_t gfp_flags) { depot_stack_handle_t handle; unsigned long entries[TRACK_ADDRS_COUNT]; unsigned int nr_entries; nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3); - handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT); + handle = stack_depot_save(entries, nr_entries, gfp_flags); return handle; } #else -static inline depot_stack_handle_t set_track_prepare(void) +static inline depot_stack_handle_t set_track_prepare(gfp_t gfp_flags) { return 0; } @@ -996,9 +996,9 @@ static void set_track_update(struct kmem_cache *s, void *object, } static __always_inline void set_track(struct kmem_cache *s, void *object, - enum track_item alloc, unsigned long addr) + enum track_item alloc, unsigned long addr, gfp_t gfp_flags) { - depot_stack_handle_t handle = set_track_prepare(); + depot_stack_handle_t handle = set_track_prepare(gfp_flags); set_track_update(s, object, alloc, addr, handle); } @@ -1926,9 +1926,9 @@ static inline bool free_debug_processing(struct kmem_cache *s, static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {} static inline int check_object(struct kmem_cache *s, struct slab *slab, void *object, u8 val) { return 1; } -static inline depot_stack_handle_t set_track_prepare(void) { return 0; } +static inline depot_stack_handle_t set_track_prepare(gfp_t gfp_flags) { return 0; } static inline void set_track(struct kmem_cache *s, void *object, - enum track_item alloc, unsigned long addr) {} + enum track_item alloc, unsigned long addr, gfp_t gfp_flags) {} static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab) {} static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, @@ -3881,9 +3881,14 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, * For debug caches here we had to go through * alloc_single_from_partial() so just store the * tracking info and return the object. + * + * Due to disabled preemption we need to disallow + * blocking. The flags are further adjusted by + * gfp_nested_mask() in stack_depot itself. */ if (s->flags & SLAB_STORE_USER) - set_track(s, freelist, TRACK_ALLOC, addr); + set_track(s, freelist, TRACK_ALLOC, addr, + gfpflags & ~(__GFP_DIRECT_RECLAIM)); return freelist; } @@ -3915,7 +3920,8 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, goto new_objects; if (s->flags & SLAB_STORE_USER) - set_track(s, freelist, TRACK_ALLOC, addr); + set_track(s, freelist, TRACK_ALLOC, addr, + gfpflags & ~(__GFP_DIRECT_RECLAIM)); return freelist; } @@ -4426,8 +4432,12 @@ static noinline void free_to_partial_list( unsigned long flags; depot_stack_handle_t handle = 0; + /* + * We cannot use GFP_NOWAIT as there are callsites where waking up + * kswapd could deadlock + */ if (s->flags & SLAB_STORE_USER) - handle = set_track_prepare(); + handle = set_track_prepare(__GFP_NOWARN); spin_lock_irqsave(&n->list_lock, flags);

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