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[REGRESSION] v5.15: UDP packets not fragmented after receiving ICMP "Fragmentation Needed" (works in v5.10)

by CHANDRA SEKHAR REDDY

Hi Team, We are observing an intermittent regression in UDP fragmentation handling between Linux kernel versions v5.10.35 and v5.15.71. Problem description: Our application sends UDP packets that exceed the path MTU. An intermediate hop returns an ICMP Type 3, Code 4 (Fragmentation Needed) message. On v5.10.35, the kernel correctly updates the Path MTU cache, and subsequent packets are fragmented as expected. On v5.15.71, although the ICMP message is received by the kernel, subsequent UDP packets are sometimes not fragmented and continue to be dropped. System details: Egress interface MTU: 9192 bytes Path MTU at intermediate hop: 1500 bytes Kernel parameter: ip_no_pmtu_disc=0 (default) Questions / request for feedback: Is this a known regression in the 5.15 kernel series? We have verified that the Path MTU cache is usually updated correctly. Is there a way to detect or log cases where the cache is not updated? If this issue has already been addressed, could you please point us to the relevant fix commit so we can backport and test it? We have reviewed several patches between v5.10.35 and v5.15.71 related to PMTU and ICMP handling and examined the code flow, but have not been able to pinpoint the root cause. Any guidance, insights, or pointers would be greatly appreciated. Best regards, Chandrasekharreddy C

2 months

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[PATCH v2] ceph: fix deadlock bugs by making iput() calls asynchronous

by Max Kellermann

The iput() function is a dangerous one - if the reference counter goes to zero, the function may block for a long time due to: - inode_wait_for_writeback() waits until writeback on this inode completes - the filesystem-specific "evict_inode" callback can do similar things; e.g. all netfs-based filesystems will call netfs_wait_for_outstanding_io() which is similar to inode_wait_for_writeback() Therefore, callers must carefully evaluate the context they're in and check whether invoking iput() is a good idea at all. Most of the time, this is not a problem because the dcache holds references to all inodes, and the dcache is usually the one to release the last reference. But this assumption is fragile. For example, under (memcg) memory pressure, the dcache shrinker is more likely to release inode references, moving the inode eviction to contexts where that was extremely unlikely to occur. Our production servers "found" at least two deadlock bugs in the Ceph filesystem that were caused by this iput() behavior: 1. Writeback may lead to iput() calls in Ceph (e.g. from ceph_put_wrbuffer_cap_refs()) which deadlocks in inode_wait_for_writeback(). Waiting for writeback completion from within writeback will obviously never be able to make any progress. This leads to blocked kworkers like this: INFO: task kworker/u777:6:1270802 blocked for more than 122 seconds. Not tainted 6.16.7-i1-es #773 task:kworker/u777:6 state:D stack:0 pid:1270802 tgid:1270802 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: writeback wb_workfn (flush-ceph-3) Call Trace: <TASK> __schedule+0x4ea/0x17d0 schedule+0x1c/0xc0 inode_wait_for_writeback+0x71/0xb0 evict+0xcf/0x200 ceph_put_wrbuffer_cap_refs+0xdd/0x220 ceph_invalidate_folio+0x97/0xc0 ceph_writepages_start+0x127b/0x14d0 do_writepages+0xba/0x150 __writeback_single_inode+0x34/0x290 writeback_sb_inodes+0x203/0x470 __writeback_inodes_wb+0x4c/0xe0 wb_writeback+0x189/0x2b0 wb_workfn+0x30b/0x3d0 process_one_work+0x143/0x2b0 worker_thread+0x30a/0x450 2. In the Ceph messenger thread (net/ceph/messenger*.c), any iput() call may invoke ceph_evict_inode() which will deadlock in netfs_wait_for_outstanding_io(); since this blocks the messenger thread, completions from the Ceph servers will not ever be received and handled. It looks like these deadlock bugs have been in the Ceph filesystem code since forever (therefore no "Fixes" tag in this patch). There may be various ways to solve this: - make iput() asynchronous and defer the actual eviction like fput() (may add overhead) - make iput() only asynchronous if I_SYNC is set (doesn't solve random things happening inside the "evict_inode" callback) - add iput_deferred() to make this asynchronous behavior/overhead optional and explicit - refactor Ceph to avoid iput() calls from within writeback and messenger (if that is even possible) - add a Ceph-specific workaround After advice from Mateusz Guzik, I decided to do the latter. The implementation is simple because it piggybacks on the existing work_struct for ceph_queue_inode_work() - ceph_inode_work() calls iput() at the end which means we can donate the last reference to it. This patch adds ceph_iput_async() and converts lots of iput() calls to it - at least those that may come through writeback and the messenger. Signed-off-by: Max Kellermann <max.kellermann(a)ionos.com> Cc: Mateusz Guzik <mjguzik(a)gmail.com> Cc: stable(a)vger.kernel.org --- v1->v2: using atomic_add_unless() instead of atomic_add_unless() to avoid letting i_count drop to zero which may cause races (thanks Mateusz Guzik) Signed-off-by: Max Kellermann <max.kellermann(a)ionos.com> --- fs/ceph/addr.c | 2 +- fs/ceph/caps.c | 16 ++++++++-------- fs/ceph/dir.c | 2 +- fs/ceph/inode.c | 34 ++++++++++++++++++++++++++++++++++ fs/ceph/mds_client.c | 30 +++++++++++++++--------------- fs/ceph/quota.c | 4 ++-- fs/ceph/snap.c | 10 +++++----- fs/ceph/super.h | 2 ++ 8 files changed, 68 insertions(+), 32 deletions(-) diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c index 322ed268f14a..fc497c91530e 100644 --- a/fs/ceph/addr.c +++ b/fs/ceph/addr.c @@ -265,7 +265,7 @@ static void finish_netfs_read(struct ceph_osd_request *req) subreq->error = err; trace_netfs_sreq(subreq, netfs_sreq_trace_io_progress); netfs_read_subreq_terminated(subreq); - iput(req->r_inode); + ceph_iput_async(req->r_inode); ceph_dec_osd_stopping_blocker(fsc->mdsc); } diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index b1a8ff612c41..af9e3ae9ab7e 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -1771,7 +1771,7 @@ void ceph_flush_snaps(struct ceph_inode_info *ci, spin_unlock(&mdsc->snap_flush_lock); if (need_put) - iput(inode); + ceph_iput_async(inode); } /* @@ -3319,7 +3319,7 @@ static void __ceph_put_cap_refs(struct ceph_inode_info *ci, int had, if (wake) wake_up_all(&ci->i_cap_wq); while (put-- > 0) - iput(inode); + ceph_iput_async(inode); } void ceph_put_cap_refs(struct ceph_inode_info *ci, int had) @@ -3419,7 +3419,7 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr, if (complete_capsnap) wake_up_all(&ci->i_cap_wq); while (put-- > 0) { - iput(inode); + ceph_iput_async(inode); } } @@ -3917,7 +3917,7 @@ static void handle_cap_flush_ack(struct inode *inode, u64 flush_tid, if (wake_mdsc) wake_up_all(&mdsc->cap_flushing_wq); if (drop) - iput(inode); + ceph_iput_async(inode); } void __ceph_remove_capsnap(struct inode *inode, struct ceph_cap_snap *capsnap, @@ -4008,7 +4008,7 @@ static void handle_cap_flushsnap_ack(struct inode *inode, u64 flush_tid, wake_up_all(&ci->i_cap_wq); if (wake_mdsc) wake_up_all(&mdsc->cap_flushing_wq); - iput(inode); + ceph_iput_async(inode); } } @@ -4557,7 +4557,7 @@ void ceph_handle_caps(struct ceph_mds_session *session, done: mutex_unlock(&session->s_mutex); done_unlocked: - iput(inode); + ceph_iput_async(inode); out: ceph_dec_mds_stopping_blocker(mdsc); @@ -4636,7 +4636,7 @@ unsigned long ceph_check_delayed_caps(struct ceph_mds_client *mdsc) doutc(cl, "on %p %llx.%llx\n", inode, ceph_vinop(inode)); ceph_check_caps(ci, 0); - iput(inode); + ceph_iput_async(inode); spin_lock(&mdsc->cap_delay_lock); } @@ -4675,7 +4675,7 @@ static void flush_dirty_session_caps(struct ceph_mds_session *s) spin_unlock(&mdsc->cap_dirty_lock); ceph_wait_on_async_create(inode); ceph_check_caps(ci, CHECK_CAPS_FLUSH); - iput(inode); + ceph_iput_async(inode); spin_lock(&mdsc->cap_dirty_lock); } spin_unlock(&mdsc->cap_dirty_lock); diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c index 32973c62c1a2..ec73ed52a227 100644 --- a/fs/ceph/dir.c +++ b/fs/ceph/dir.c @@ -1290,7 +1290,7 @@ static void ceph_async_unlink_cb(struct ceph_mds_client *mdsc, ceph_mdsc_free_path_info(&path_info); } out: - iput(req->r_old_inode); + ceph_iput_async(req->r_old_inode); ceph_mdsc_release_dir_caps(req); } diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c index f67025465de0..d7c0ed82bf62 100644 --- a/fs/ceph/inode.c +++ b/fs/ceph/inode.c @@ -2191,6 +2191,40 @@ void ceph_queue_inode_work(struct inode *inode, int work_bit) } } +/** + * Queue an asynchronous iput() call in a worker thread. Use this + * instead of iput() in contexts where evicting the inode is unsafe. + * For example, inode eviction may cause deadlocks in + * inode_wait_for_writeback() (when called from within writeback) or + * in netfs_wait_for_outstanding_io() (when called from within the + * Ceph messenger). + */ +void ceph_iput_async(struct inode *inode) +{ + if (unlikely(!inode)) + return; + + if (likely(atomic_add_unless(&inode->i_count, -1, 1))) + /* somebody else is holding another reference - + * nothing left to do for us + */ + return; + + doutc(ceph_inode_to_fs_client(inode)->client, "%p %llx.%llx\n", inode, ceph_vinop(inode)); + + /* simply queue a ceph_inode_work() (donating the remaining + * reference) without setting i_work_mask bit; other than + * putting the reference, there is nothing to do + */ + WARN_ON_ONCE(!queue_work(ceph_inode_to_fs_client(inode)->inode_wq, + &ceph_inode(inode)->i_work)); + + /* note: queue_work() cannot fail; it i_work were already + * queued, then it would be holding another reference, but no + * such reference exists + */ +} + static void ceph_do_invalidate_pages(struct inode *inode) { struct ceph_client *cl = ceph_inode_to_client(inode); diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index 3bc72b47fe4d..22d75c3be5a8 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -1097,14 +1097,14 @@ void ceph_mdsc_release_request(struct kref *kref) ceph_msg_put(req->r_reply); if (req->r_inode) { ceph_put_cap_refs(ceph_inode(req->r_inode), CEPH_CAP_PIN); - iput(req->r_inode); + ceph_iput_async(req->r_inode); } if (req->r_parent) { ceph_put_cap_refs(ceph_inode(req->r_parent), CEPH_CAP_PIN); - iput(req->r_parent); + ceph_iput_async(req->r_parent); } - iput(req->r_target_inode); - iput(req->r_new_inode); + ceph_iput_async(req->r_target_inode); + ceph_iput_async(req->r_new_inode); if (req->r_dentry) dput(req->r_dentry); if (req->r_old_dentry) @@ -1118,7 +1118,7 @@ void ceph_mdsc_release_request(struct kref *kref) */ ceph_put_cap_refs(ceph_inode(req->r_old_dentry_dir), CEPH_CAP_PIN); - iput(req->r_old_dentry_dir); + ceph_iput_async(req->r_old_dentry_dir); } kfree(req->r_path1); kfree(req->r_path2); @@ -1240,7 +1240,7 @@ static void __unregister_request(struct ceph_mds_client *mdsc, } if (req->r_unsafe_dir) { - iput(req->r_unsafe_dir); + ceph_iput_async(req->r_unsafe_dir); req->r_unsafe_dir = NULL; } @@ -1413,7 +1413,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc, cap = rb_entry(rb_first(&ci->i_caps), struct ceph_cap, ci_node); if (!cap) { spin_unlock(&ci->i_ceph_lock); - iput(inode); + ceph_iput_async(inode); goto random; } mds = cap->session->s_mds; @@ -1422,7 +1422,7 @@ static int __choose_mds(struct ceph_mds_client *mdsc, cap == ci->i_auth_cap ? "auth " : "", cap); spin_unlock(&ci->i_ceph_lock); out: - iput(inode); + ceph_iput_async(inode); return mds; random: @@ -1841,7 +1841,7 @@ int ceph_iterate_session_caps(struct ceph_mds_session *session, spin_unlock(&session->s_cap_lock); if (last_inode) { - iput(last_inode); + ceph_iput_async(last_inode); last_inode = NULL; } if (old_cap) { @@ -1874,7 +1874,7 @@ int ceph_iterate_session_caps(struct ceph_mds_session *session, session->s_cap_iterator = NULL; spin_unlock(&session->s_cap_lock); - iput(last_inode); + ceph_iput_async(last_inode); if (old_cap) ceph_put_cap(session->s_mdsc, old_cap); @@ -1904,7 +1904,7 @@ static int remove_session_caps_cb(struct inode *inode, int mds, void *arg) if (invalidate) ceph_queue_invalidate(inode); while (iputs--) - iput(inode); + ceph_iput_async(inode); return 0; } @@ -1944,7 +1944,7 @@ static void remove_session_caps(struct ceph_mds_session *session) spin_unlock(&session->s_cap_lock); inode = ceph_find_inode(sb, vino); - iput(inode); + ceph_iput_async(inode); spin_lock(&session->s_cap_lock); } @@ -2512,7 +2512,7 @@ static void ceph_cap_unlink_work(struct work_struct *work) doutc(cl, "on %p %llx.%llx\n", inode, ceph_vinop(inode)); ceph_check_caps(ci, CHECK_CAPS_FLUSH); - iput(inode); + ceph_iput_async(inode); spin_lock(&mdsc->cap_delay_lock); } } @@ -3933,7 +3933,7 @@ static void handle_reply(struct ceph_mds_session *session, struct ceph_msg *msg) !req->r_reply_info.has_create_ino) { /* This should never happen on an async create */ WARN_ON_ONCE(req->r_deleg_ino); - iput(in); + ceph_iput_async(in); in = NULL; } @@ -5313,7 +5313,7 @@ static void handle_lease(struct ceph_mds_client *mdsc, out: mutex_unlock(&session->s_mutex); - iput(inode); + ceph_iput_async(inode); ceph_dec_mds_stopping_blocker(mdsc); return; diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c index d90eda19bcc4..bba00f8926e6 100644 --- a/fs/ceph/quota.c +++ b/fs/ceph/quota.c @@ -76,7 +76,7 @@ void ceph_handle_quota(struct ceph_mds_client *mdsc, le64_to_cpu(h->max_files)); spin_unlock(&ci->i_ceph_lock); - iput(inode); + ceph_iput_async(inode); out: ceph_dec_mds_stopping_blocker(mdsc); } @@ -190,7 +190,7 @@ void ceph_cleanup_quotarealms_inodes(struct ceph_mds_client *mdsc) node = rb_first(&mdsc->quotarealms_inodes); qri = rb_entry(node, struct ceph_quotarealm_inode, node); rb_erase(node, &mdsc->quotarealms_inodes); - iput(qri->inode); + ceph_iput_async(qri->inode); kfree(qri); } mutex_unlock(&mdsc->quotarealms_inodes_mutex); diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index c65f2b202b2b..19f097e79b3c 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -735,7 +735,7 @@ static void queue_realm_cap_snaps(struct ceph_mds_client *mdsc, if (!inode) continue; spin_unlock(&realm->inodes_with_caps_lock); - iput(lastinode); + ceph_iput_async(lastinode); lastinode = inode; /* @@ -762,7 +762,7 @@ static void queue_realm_cap_snaps(struct ceph_mds_client *mdsc, spin_lock(&realm->inodes_with_caps_lock); } spin_unlock(&realm->inodes_with_caps_lock); - iput(lastinode); + ceph_iput_async(lastinode); if (capsnap) kmem_cache_free(ceph_cap_snap_cachep, capsnap); @@ -955,7 +955,7 @@ static void flush_snaps(struct ceph_mds_client *mdsc) ihold(inode); spin_unlock(&mdsc->snap_flush_lock); ceph_flush_snaps(ci, &session); - iput(inode); + ceph_iput_async(inode); spin_lock(&mdsc->snap_flush_lock); } spin_unlock(&mdsc->snap_flush_lock); @@ -1116,12 +1116,12 @@ void ceph_handle_snap(struct ceph_mds_client *mdsc, ceph_get_snap_realm(mdsc, realm); ceph_change_snap_realm(inode, realm); spin_unlock(&ci->i_ceph_lock); - iput(inode); + ceph_iput_async(inode); continue; skip_inode: spin_unlock(&ci->i_ceph_lock); - iput(inode); + ceph_iput_async(inode); } /* we may have taken some of the old realm's children. */ diff --git a/fs/ceph/super.h b/fs/ceph/super.h index cf176aab0f82..361a72a67bb8 100644 --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -1085,6 +1085,8 @@ static inline void ceph_queue_flush_snaps(struct inode *inode) ceph_queue_inode_work(inode, CEPH_I_WORK_FLUSH_SNAPS); } +void ceph_iput_async(struct inode *inode); + extern int ceph_try_to_choose_auth_mds(struct inode *inode, int mask); extern int __ceph_do_getattr(struct inode *inode, struct page *locked_page, int mask, bool force); -- 2.47.3

2 months

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New September Order. 01646 Thursday, September 18, 2025 at 06:33:48 AM

by Info - Albinayah 368

Hi Stable, Please provide a quote for your products: Include: 1.Pricing (per unit) 2.Delivery cost & timeline 3.Quote expiry date Deadline: September Thanks! Kamal Prasad Albinayah Trading

2 months

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+ selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled.patch added to mm-new branch

by Andrew Morton

The patch titled Subject: selftests/mm: skip soft-dirty tests when CONFIG_MEM_SOFT_DIRTY is disabled has been added to the -mm mm-new branch. Its filename is selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patche… This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Lance Yang <lance.yang(a)linux.dev> Subject: selftests/mm: skip soft-dirty tests when CONFIG_MEM_SOFT_DIRTY is disabled Date: Wed, 17 Sep 2025 21:31:37 +0800 The madv_populate and soft-dirty kselftests currently fail on systems where CONFIG_MEM_SOFT_DIRTY is disabled. Introduce a new helper softdirty_supported() into vm_util.c/h to ensure tests are properly skipped when the feature is not enabled. Link: https://lkml.kernel.org/r/20250917133137.62802-1-lance.yang@linux.dev Fixes: 9f3265db6ae8 ("selftests: vm: add test for Soft-Dirty PTE bit") Signed-off-by: Lance Yang <lance.yang(a)linux.dev> Acked-by: David Hildenbrand <david(a)redhat.com> Suggested-by: David Hildenbrand <david(a)redhat.com> Cc: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Gabriel Krisman Bertazi <krisman(a)collabora.com> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> --- tools/testing/selftests/mm/madv_populate.c | 21 +------------------ tools/testing/selftests/mm/soft-dirty.c | 5 +++- tools/testing/selftests/mm/vm_util.c | 17 +++++++++++++++ tools/testing/selftests/mm/vm_util.h | 1 4 files changed, 24 insertions(+), 20 deletions(-) --- a/tools/testing/selftests/mm/madv_populate.c~selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled +++ a/tools/testing/selftests/mm/madv_populate.c @@ -264,23 +264,6 @@ static void test_softdirty(void) munmap(addr, SIZE); } -static int system_has_softdirty(void) -{ - /* - * There is no way to check if the kernel supports soft-dirty, other - * than by writing to a page and seeing if the bit was set. But the - * tests are intended to check that the bit gets set when it should, so - * doing that check would turn a potentially legitimate fail into a - * skip. Fortunately, we know for sure that arm64 does not support - * soft-dirty. So for now, let's just use the arch as a corse guide. - */ -#if defined(__aarch64__) - return 0; -#else - return 1; -#endif -} - int main(int argc, char **argv) { int nr_tests = 16; @@ -288,7 +271,7 @@ int main(int argc, char **argv) pagesize = getpagesize(); - if (system_has_softdirty()) + if (softdirty_supported()) nr_tests += 5; ksft_print_header(); @@ -300,7 +283,7 @@ int main(int argc, char **argv) test_holes(); test_populate_read(); test_populate_write(); - if (system_has_softdirty()) + if (softdirty_supported()) test_softdirty(); err = ksft_get_fail_cnt(); --- a/tools/testing/selftests/mm/soft-dirty.c~selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled +++ a/tools/testing/selftests/mm/soft-dirty.c @@ -200,8 +200,11 @@ int main(int argc, char **argv) int pagesize; ksft_print_header(); - ksft_set_plan(15); + if (!softdirty_supported()) + ksft_exit_skip("soft-dirty is not support\n"); + + ksft_set_plan(15); pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY); if (pagemap_fd < 0) ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH); --- a/tools/testing/selftests/mm/vm_util.c~selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled +++ a/tools/testing/selftests/mm/vm_util.c @@ -449,6 +449,23 @@ bool check_vmflag_pfnmap(void *addr) return check_vmflag(addr, "pf"); } +bool softdirty_supported(void) +{ + char *addr; + bool supported = false; + const size_t pagesize = getpagesize(); + + /* New mappings are expected to be marked with VM_SOFTDIRTY (sd). */ + addr = mmap(0, pagesize, PROT_READ | PROT_WRITE, + MAP_ANONYMOUS | MAP_PRIVATE, 0, 0); + if (!addr) + ksft_exit_fail_msg("mmap failed\n"); + + supported = check_vmflag(addr, "sd"); + munmap(addr, pagesize); + return supported; +} + /* * Open an fd at /proc/$pid/maps and configure procmap_out ready for * PROCMAP_QUERY query. Returns 0 on success, or an error code otherwise. --- a/tools/testing/selftests/mm/vm_util.h~selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled +++ a/tools/testing/selftests/mm/vm_util.h @@ -104,6 +104,7 @@ bool find_vma_procmap(struct procmap_fd int close_procmap(struct procmap_fd *procmap); int write_sysfs(const char *file_path, unsigned long val); int read_sysfs(const char *file_path, unsigned long *val); +bool softdirty_supported(void); static inline int open_self_procmap(struct procmap_fd *procmap_out) { _ Patches currently in -mm which might be from lance.yang(a)linux.dev are hung_task-fix-warnings-caused-by-unaligned-lock-pointers.patch mm-skip-mlocked-thps-that-are-underused-early-in-deferred_split_scan.patch selftests-mm-skip-soft-dirty-tests-when-config_mem_soft_dirty-is-disabled.patch

2 months

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[PATCH 03/39] Bluetooth: L2CAP: Fix L2CAP MTU negotiation

by julian-lagattuta

From: Frédéric Danis <frederic.danis(a)collabora.com> OBEX download from iPhone is currently slow due to small packet size used to transfer data which doesn't follow the MTU negotiated during L2CAP connection, i.e. 672 bytes instead of 32767: < ACL Data TX: Handle 11 flags 0x00 dlen 12 L2CAP: Connection Request (0x02) ident 18 len 4 PSM: 4103 (0x1007) Source CID: 72 > ACL Data RX: Handle 11 flags 0x02 dlen 16 L2CAP: Connection Response (0x03) ident 18 len 8 Destination CID: 14608 Source CID: 72 Result: Connection successful (0x0000) Status: No further information available (0x0000) < ACL Data TX: Handle 11 flags 0x00 dlen 27 L2CAP: Configure Request (0x04) ident 20 len 19 Destination CID: 14608 Flags: 0x0000 Option: Maximum Transmission Unit (0x01) [mandatory] MTU: 32767 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 63 Max transmit: 3 Retransmission timeout: 2000 Monitor timeout: 12000 Maximum PDU size: 1009 > ACL Data RX: Handle 11 flags 0x02 dlen 26 L2CAP: Configure Request (0x04) ident 72 len 18 Destination CID: 72 Flags: 0x0000 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 32 Max transmit: 255 Retransmission timeout: 0 Monitor timeout: 0 Maximum PDU size: 65527 Option: Frame Check Sequence (0x05) [mandatory] FCS: 16-bit FCS (0x01) < ACL Data TX: Handle 11 flags 0x00 dlen 29 L2CAP: Configure Response (0x05) ident 72 len 21 Source CID: 14608 Flags: 0x0000 Result: Success (0x0000) Option: Maximum Transmission Unit (0x01) [mandatory] MTU: 672 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 32 Max transmit: 255 Retransmission timeout: 2000 Monitor timeout: 12000 Maximum PDU size: 1009 > ACL Data RX: Handle 11 flags 0x02 dlen 32 L2CAP: Configure Response (0x05) ident 20 len 24 Source CID: 72 Flags: 0x0000 Result: Success (0x0000) Option: Maximum Transmission Unit (0x01) [mandatory] MTU: 32767 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 63 Max transmit: 3 Retransmission timeout: 2000 Monitor timeout: 12000 Maximum PDU size: 1009 Option: Frame Check Sequence (0x05) [mandatory] FCS: 16-bit FCS (0x01) ... > ACL Data RX: Handle 11 flags 0x02 dlen 680 Channel: 72 len 676 ctrl 0x0202 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8} I-frame: Unsegmented TxSeq 1 ReqSeq 2 < ACL Data TX: Handle 11 flags 0x00 dlen 13 Channel: 14608 len 9 ctrl 0x0204 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8} I-frame: Unsegmented TxSeq 2 ReqSeq 2 > ACL Data RX: Handle 11 flags 0x02 dlen 680 Channel: 72 len 676 ctrl 0x0304 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8} I-frame: Unsegmented TxSeq 2 ReqSeq 3 The MTUs are negotiated for each direction. In this traces 32767 for iPhone->localhost and no MTU for localhost->iPhone, which based on '4.4 L2CAP_CONFIGURATION_REQ' (Core specification v5.4, Vol. 3, Part A): The only parameters that should be included in the L2CAP_CONFIGURATION_REQ packet are those that require different values than the default or previously agreed values. ... Any missing configuration parameters are assumed to have their most recently explicitly or implicitly accepted values. and '5.1 Maximum transmission unit (MTU)': If the remote device sends a positive L2CAP_CONFIGURATION_RSP packet it should include the actual MTU to be used on this channel for traffic flowing into the local device. ... The default value is 672 octets. is set by BlueZ to 672 bytes. It seems that the iPhone used the lowest negotiated value to transfer data to the localhost instead of the negotiated one for the incoming direction. This could be fixed by using the MTU negotiated for the other direction, if exists, in the L2CAP_CONFIGURATION_RSP. This allows to use segmented packets as in the following traces: < ACL Data TX: Handle 11 flags 0x00 dlen 12 L2CAP: Connection Request (0x02) ident 22 len 4 PSM: 4103 (0x1007) Source CID: 72 < ACL Data TX: Handle 11 flags 0x00 dlen 27 L2CAP: Configure Request (0x04) ident 24 len 19 Destination CID: 2832 Flags: 0x0000 Option: Maximum Transmission Unit (0x01) [mandatory] MTU: 32767 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 63 Max transmit: 3 Retransmission timeout: 2000 Monitor timeout: 12000 Maximum PDU size: 1009 > ACL Data RX: Handle 11 flags 0x02 dlen 26 L2CAP: Configure Request (0x04) ident 15 len 18 Destination CID: 72 Flags: 0x0000 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 32 Max transmit: 255 Retransmission timeout: 0 Monitor timeout: 0 Maximum PDU size: 65527 Option: Frame Check Sequence (0x05) [mandatory] FCS: 16-bit FCS (0x01) < ACL Data TX: Handle 11 flags 0x00 dlen 29 L2CAP: Configure Response (0x05) ident 15 len 21 Source CID: 2832 Flags: 0x0000 Result: Success (0x0000) Option: Maximum Transmission Unit (0x01) [mandatory] MTU: 32767 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 32 Max transmit: 255 Retransmission timeout: 2000 Monitor timeout: 12000 Maximum PDU size: 1009 > ACL Data RX: Handle 11 flags 0x02 dlen 32 L2CAP: Configure Response (0x05) ident 24 len 24 Source CID: 72 Flags: 0x0000 Result: Success (0x0000) Option: Maximum Transmission Unit (0x01) [mandatory] MTU: 32767 Option: Retransmission and Flow Control (0x04) [mandatory] Mode: Enhanced Retransmission (0x03) TX window size: 63 Max transmit: 3 Retransmission timeout: 2000 Monitor timeout: 12000 Maximum PDU size: 1009 Option: Frame Check Sequence (0x05) [mandatory] FCS: 16-bit FCS (0x01) ... > ACL Data RX: Handle 11 flags 0x02 dlen 1009 Channel: 72 len 1005 ctrl 0x4202 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8} I-frame: Start (len 21884) TxSeq 1 ReqSeq 2 > ACL Data RX: Handle 11 flags 0x02 dlen 1009 Channel: 72 len 1005 ctrl 0xc204 [PSM 4103 mode Enhanced Retransmission (0x03)] {chan 8} I-frame: Continuation TxSeq 2 ReqSeq 2 This has been tested with kernel 5.4 and BlueZ 5.77. Cc: stable(a)vger.kernel.org Signed-off-by: Frédéric Danis <frederic.danis(a)collabora.com> Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz(a)intel.com> --- net/bluetooth/l2cap_core.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index a5bde5db58ef..40daa38276f3 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -3415,7 +3415,7 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data struct l2cap_conf_rfc rfc = { .mode = L2CAP_MODE_BASIC }; struct l2cap_conf_efs efs; u8 remote_efs = 0; - u16 mtu = L2CAP_DEFAULT_MTU; + u16 mtu = 0; u16 result = L2CAP_CONF_SUCCESS; u16 size; @@ -3520,6 +3520,13 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data, size_t data /* Configure output options and let the other side know * which ones we don't like. */ + /* If MTU is not provided in configure request, use the most recently + * explicitly or implicitly accepted value for the other direction, + * or the default value. + */ + if (mtu == 0) + mtu = chan->imtu ? chan->imtu : L2CAP_DEFAULT_MTU; + if (mtu < L2CAP_DEFAULT_MIN_MTU) result = L2CAP_CONF_UNACCEPT; else { -- 2.45.2

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Re: [PATCH net] net: clear sk->sk_ino in sk_set_socket(sk, NULL)

by Eric Dumazet

On Wed, Sep 17, 2025 at 10:03 AM Andrei Vagin <avagin(a)google.com> wrote: > > is > > On Wed, Sep 17, 2025 at 8:59 AM Eric Dumazet <edumazet(a)google.com> wrote: > > > > On Wed, Sep 17, 2025 at 8:39 AM Andrei Vagin <avagin(a)google.com> wrote: > > > > > > On Wed, Sep 17, 2025 at 6:53 AM Eric Dumazet <edumazet(a)google.com> wrote: > > > > > > > > Andrei Vagin reported that blamed commit broke CRIU. > > > > > > > > Indeed, while we want to keep sk_uid unchanged when a socket > > > > is cloned, we want to clear sk->sk_ino. > > > > > > > > Otherwise, sock_diag might report multiple sockets sharing > > > > the same inode number. > > > > > > > > Move the clearing part from sock_orphan() to sk_set_socket(sk, NULL), > > > > called both from sock_orphan() and sk_clone_lock(). > > > > > > > > Fixes: 5d6b58c932ec ("net: lockless sock_i_ino()") > > > > Closes: https://lore.kernel.org/netdev/aMhX-VnXkYDpKd9V@google.com/ > > > > Closes: https://github.com/checkpoint-restore/criu/issues/2744 > > > > Reported-by: Andrei Vagin <avagin(a)google.com> > > > > Signed-off-by: Eric Dumazet <edumazet(a)google.com> > > > > > > Acked-by: Andrei Vagin <avagin(a)google.com> > > > I think we need to add `Cc: stable(a)vger.kernel.org`. > > > > I never do this. Note that the prior patch had no such CC. > > The original patch has been ported to the v6.16 kernels. According to the > kernel documentation > (https://www.kernel.org/doc/html/v6.5/process/stable-kernel-rules.html), > adding Cc: stable(a)vger.kernel.org is required for automatic porting into > stable trees. Without this tag, someone will likely need to manually request > that this patch be ported. This is my understanding of how the stable > branch process works, sorry if I missed something. Andrei, I think I know pretty well what I am doing. You do not have to explain to me anything. Thank you.

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Mate dar vo vyske dva miliony patsto tisic euro

by Dr Leonard Valentinovic Blavatnik

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[PATCH] kmsan: Fix out-of-bounds access to shadow memory

by Eric Biggers

Running sha224_kunit on a KMSAN-enabled kernel results in a crash in kmsan_internal_set_shadow_origin(): BUG: unable to handle page fault for address: ffffbc3840291000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary) Tainted: [N]=TEST Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100 [...] Call Trace: <TASK> __msan_memset+0xee/0x1a0 sha224_final+0x9e/0x350 test_hash_buffer_overruns+0x46f/0x5f0 ? kmsan_get_shadow_origin_ptr+0x46/0xa0 ? __pfx_test_hash_buffer_overruns+0x10/0x10 kunit_try_run_case+0x198/0xa00 This occurs when memset() is called on a buffer that is not 4-byte aligned and extends to the end of a guard page, i.e. the next page is unmapped. The bug is that the loop at the end of kmsan_internal_set_shadow_origin() accesses the wrong shadow memory bytes when the address is not 4-byte aligned. Since each 4 bytes are associated with an origin, it rounds the address and size so that it can access all the origins that contain the buffer. However, when it checks the corresponding shadow bytes for a particular origin, it incorrectly uses the original unrounded shadow address. This results in reads from shadow memory beyond the end of the buffer's shadow memory, which crashes when that memory is not mapped. To fix this, correctly align the shadow address before accessing the 4 shadow bytes corresponding to each origin. Fixes: 2ef3cec44c60 ("kmsan: do not wipe out origin when doing partial unpoisoning") Cc: stable(a)vger.kernel.org Signed-off-by: Eric Biggers <ebiggers(a)kernel.org> --- mm/kmsan/core.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/kmsan/core.c b/mm/kmsan/core.c index 1ea711786c522..8bca7fece47f0 100644 --- a/mm/kmsan/core.c +++ b/mm/kmsan/core.c @@ -193,11 +193,12 @@ depot_stack_handle_t kmsan_internal_chain_origin(depot_stack_handle_t id) void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, u32 origin, bool checked) { u64 address = (u64)addr; - u32 *shadow_start, *origin_start; + void *shadow_start; + u32 *aligned_shadow, *origin_start; size_t pad = 0; KMSAN_WARN_ON(!kmsan_metadata_is_contiguous(addr, size)); shadow_start = kmsan_get_metadata(addr, KMSAN_META_SHADOW); if (!shadow_start) { @@ -212,13 +213,16 @@ void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, } return; } __memset(shadow_start, b, size); - if (!IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) { + if (IS_ALIGNED(address, KMSAN_ORIGIN_SIZE)) { + aligned_shadow = shadow_start; + } else { pad = address % KMSAN_ORIGIN_SIZE; address -= pad; + aligned_shadow = shadow_start - pad; size += pad; } size = ALIGN(size, KMSAN_ORIGIN_SIZE); origin_start = (u32 *)kmsan_get_metadata((void *)address, KMSAN_META_ORIGIN); @@ -228,11 +232,11 @@ void kmsan_internal_set_shadow_origin(void *addr, size_t size, int b, * and unconditionally overwrite the old origin slot. * If the new origin is zero, overwrite the old origin slot iff the * corresponding shadow slot is zero. */ for (int i = 0; i < size / KMSAN_ORIGIN_SIZE; i++) { - if (origin || !shadow_start[i]) + if (origin || !aligned_shadow[i]) origin_start[i] = origin; } } struct page *kmsan_vmalloc_to_page_or_null(void *vaddr) base-commit: 1b237f190eb3d36f52dffe07a40b5eb210280e00 -- 2.50.1

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[PATCH] wifi: mt76: Fix DTS power-limits on little endian systems

by Sven Eckelmann (Plasma Cloud)

The power-limits for ru and mcs and stored in the devicetree as bytewise array (often with sizes which are not a multiple of 4). These arrays have a prefix which defines for how many modes a line is applied. This prefix is also only a byte - but the code still tried to fix the endianness of this byte with a be32 operation. As result, loading was mostly failing or was sending completely unexpected values to the firmware. Since the other rates are also stored in the devicetree as bytewise arrays, just drop the u32 access + be32_to_cpu conversion and directly access them as bytes arrays. Cc: stable(a)vger.kernel.org Fixes: 22b980badc0f ("mt76: add functions for parsing rate power limits from DT") Fixes: 273943f4abd4 ("wifi: mt76: Fix DTS power-limits on little endian systems") Signed-off-by: Sven Eckelmann (Plasma Cloud) <se(a)simonwunderlich.de> --- drivers/net/wireless/mediatek/mt76/eeprom.c | 37 +++++++++++++++++++---------- 1 file changed, 24 insertions(+), 13 deletions(-) diff --git a/drivers/net/wireless/mediatek/mt76/eeprom.c b/drivers/net/wireless/mediatek/mt76/eeprom.c index a987c5e4eff6c6b0a014b4b069dc1259ffa82d31..6ce8e4af18fe53c10a0cb7290bf65962ce9cdde4 100644 --- a/drivers/net/wireless/mediatek/mt76/eeprom.c +++ b/drivers/net/wireless/mediatek/mt76/eeprom.c @@ -253,6 +253,19 @@ mt76_get_of_array(struct device_node *np, char *name, size_t *len, int min) return prop->value; } +static const s8 * +mt76_get_of_array_s8(struct device_node *np, char *name, size_t *len, int min) +{ + struct property *prop = of_find_property(np, name, NULL); + + if (!prop || !prop->value || prop->length < min) + return NULL; + + *len = prop->length; + + return prop->value; +} + struct device_node * mt76_find_channel_node(struct device_node *np, struct ieee80211_channel *chan) { @@ -294,7 +307,7 @@ mt76_get_txs_delta(struct device_node *np, u8 nss) } static void -mt76_apply_array_limit(s8 *pwr, size_t pwr_len, const __be32 *data, +mt76_apply_array_limit(s8 *pwr, size_t pwr_len, const s8 *data, s8 target_power, s8 nss_delta, s8 *max_power) { int i; @@ -303,15 +316,14 @@ mt76_apply_array_limit(s8 *pwr, size_t pwr_len, const __be32 *data, return; for (i = 0; i < pwr_len; i++) { - pwr[i] = min_t(s8, target_power, - be32_to_cpu(data[i]) + nss_delta); + pwr[i] = min_t(s8, target_power, data[i] + nss_delta); *max_power = max(*max_power, pwr[i]); } } static void mt76_apply_multi_array_limit(s8 *pwr, size_t pwr_len, s8 pwr_num, - const __be32 *data, size_t len, s8 target_power, + const s8 *data, size_t len, s8 target_power, s8 nss_delta, s8 *max_power) { int i, cur; @@ -319,8 +331,7 @@ mt76_apply_multi_array_limit(s8 *pwr, size_t pwr_len, s8 pwr_num, if (!data) return; - len /= 4; - cur = be32_to_cpu(data[0]); + cur = data[0]; for (i = 0; i < pwr_num; i++) { if (len < pwr_len + 1) break; @@ -335,7 +346,7 @@ mt76_apply_multi_array_limit(s8 *pwr, size_t pwr_len, s8 pwr_num, if (!len) break; - cur = be32_to_cpu(data[0]); + cur = data[0]; } } @@ -346,7 +357,7 @@ s8 mt76_get_rate_power_limits(struct mt76_phy *phy, { struct mt76_dev *dev = phy->dev; struct device_node *np; - const __be32 *val; + const s8 *val; char name[16]; u32 mcs_rates = dev->drv->mcs_rates; u32 ru_rates = ARRAY_SIZE(dest->ru[0]); @@ -392,21 +403,21 @@ s8 mt76_get_rate_power_limits(struct mt76_phy *phy, txs_delta = mt76_get_txs_delta(np, hweight16(phy->chainmask)); - val = mt76_get_of_array(np, "rates-cck", &len, ARRAY_SIZE(dest->cck)); + val = mt76_get_of_array_s8(np, "rates-cck", &len, ARRAY_SIZE(dest->cck)); mt76_apply_array_limit(dest->cck, ARRAY_SIZE(dest->cck), val, target_power, txs_delta, &max_power); - val = mt76_get_of_array(np, "rates-ofdm", - &len, ARRAY_SIZE(dest->ofdm)); + val = mt76_get_of_array_s8(np, "rates-ofdm", + &len, ARRAY_SIZE(dest->ofdm)); mt76_apply_array_limit(dest->ofdm, ARRAY_SIZE(dest->ofdm), val, target_power, txs_delta, &max_power); - val = mt76_get_of_array(np, "rates-mcs", &len, mcs_rates + 1); + val = mt76_get_of_array_s8(np, "rates-mcs", &len, mcs_rates + 1); mt76_apply_multi_array_limit(dest->mcs[0], ARRAY_SIZE(dest->mcs[0]), ARRAY_SIZE(dest->mcs), val, len, target_power, txs_delta, &max_power); - val = mt76_get_of_array(np, "rates-ru", &len, ru_rates + 1); + val = mt76_get_of_array_s8(np, "rates-ru", &len, ru_rates + 1); mt76_apply_multi_array_limit(dest->ru[0], ARRAY_SIZE(dest->ru[0]), ARRAY_SIZE(dest->ru), val, len, target_power, txs_delta, &max_power); --- base-commit: b36d55610215a976267197ddc914902c494705d7 change-id: 20250917-fix-power-limits-5ce07b993681 Best regards, -- Sven Eckelmann (Plasma Cloud) <se(a)simonwunderlich.de>

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FAILED: patch "[PATCH] serial: sc16is7xx: fix bug in flow control levels init" 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 535fd4c98452c87537a40610abba45daf5761ec6 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025091722-chatter-dyslexia-7db3@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 535fd4c98452c87537a40610abba45daf5761ec6 Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve <hvilleneuve(a)dimonoff.com> Date: Thu, 31 Jul 2025 08:44:50 -0400 Subject: [PATCH] serial: sc16is7xx: fix bug in flow control levels init When trying to set MCR[2], XON1 is incorrectly accessed instead. And when writing to the TCR register to configure flow control levels, we are incorrectly writing to the MSR register. The default value of $00 is then used for TCR, which means that selectable trigger levels in FCR are used in place of TCR. TCR/TLR access requires EFR[4] (enable enhanced functions) and MCR[2] to be set. EFR[4] is already set in probe(). MCR access requires LCR[7] to be zero. Since LCR is set to $BF when trying to set MCR[2], XON1 is incorrectly accessed instead because MCR shares the same address space as XON1. Since MCR[2] is unmodified and still zero, when writing to TCR we are in fact writing to MSR because TCR/TLR registers share the same address space as MSR/SPR. Fix by first removing useless reconfiguration of EFR[4] (enable enhanced functions), as it is already enabled in sc16is7xx_probe() since commit 43c51bb573aa ("sc16is7xx: make sure device is in suspend once probed"). Now LCR is $00, which means that MCR access is enabled. Also remove regcache_cache_bypass() calls since we no longer access the enhanced registers set, and TCR is already declared as volatile (in fact by declaring MSR as volatile, which shares the same address). Finally disable access to TCR/TLR registers after modifying them by clearing MCR[2]. Note: the comment about "... and internal clock div" is wrong and can be ignored/removed as access to internal clock div registers (DLL/DLH) is permitted only when LCR[7] is logic 1, not when enhanced features is enabled. And DLL/DLH access is not needed in sc16is7xx_startup(). Fixes: dfeae619d781 ("serial: sc16is7xx") Cc: stable(a)vger.kernel.org Signed-off-by: Hugo Villeneuve <hvilleneuve(a)dimonoff.com> Link: https://lore.kernel.org/r/20250731124451.1108864-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 3f38fba8f6ea..a668e0bb26b3 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1177,17 +1177,6 @@ static int sc16is7xx_startup(struct uart_port *port) sc16is7xx_port_write(port, SC16IS7XX_FCR_REG, SC16IS7XX_FCR_FIFO_BIT); - /* Enable EFR */ - sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, - SC16IS7XX_LCR_CONF_MODE_B); - - regcache_cache_bypass(one->regmap, true); - - /* Enable write access to enhanced features and internal clock div */ - sc16is7xx_port_update(port, SC16IS7XX_EFR_REG, - SC16IS7XX_EFR_ENABLE_BIT, - SC16IS7XX_EFR_ENABLE_BIT); - /* Enable TCR/TLR */ sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_TCRTLR_BIT, @@ -1199,7 +1188,8 @@ static int sc16is7xx_startup(struct uart_port *port) SC16IS7XX_TCR_RX_RESUME(24) | SC16IS7XX_TCR_RX_HALT(48)); - regcache_cache_bypass(one->regmap, false); + /* Disable TCR/TLR access */ + sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_TCRTLR_BIT, 0); /* Now, initialize the UART */ sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_WORD_LEN_8);

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