January 2025 - Linux-stable-mirror

[PATCH v2] mm: zswap: properly synchronize freeing resources during CPU hotunplug

by Yosry Ahmed

In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the current CPU at the beginning of the operation is retrieved and used throughout. However, since neither preemption nor migration are disabled, it is possible that the operation continues on a different CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as some of the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead() (i.e. acomp_ctx.buffer, acomp_ctx.req, or acomp_ctx.acomp). The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when the switch to the crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was retrieved using get_cpu_ptr() which disables preemption and makes sure the CPU cannot go away from under us. Preemption cannot be disabled with the crypto_acomp API as a sleepable context is needed. Use the acomp_ctx.mutex to synchronize CPU hotplug callbacks allocating and freeing resources with compression/decompression paths. Make sure that acomp_ctx.req is NULL when the resources are freed. In the compression/decompression paths, check if acomp_ctx.req is NULL after acquiring the mutex (meaning the CPU was offlined) and retry on the new CPU. The initialization of acomp_ctx.mutex is moved from the CPU hotplug callback to the pool initialization where it belongs (where the mutex is allocated). In addition to adding clarity, this makes sure that CPU hotplug cannot reinitialize a mutex that is already locked by compression/decompression. Previously a fix was attempted by holding cpus_read_lock() [1]. This would have caused a potential deadlock as it is possible for code already holding the lock to fall into reclaim and enter zswap (causing a deadlock). A fix was also attempted using SRCU for synchronization, but Johannes pointed out that synchronize_srcu() cannot be used in CPU hotplug notifiers [2]. Alternative fixes that were considered/attempted and could have worked: - Refcounting the per-CPU acomp_ctx. This involves complexity in handling the race between the refcount dropping to zero in zswap_[de]compress() and the refcount being re-initialized when the CPU is onlined. - Disabling migration before getting the per-CPU acomp_ctx [3], but that's discouraged and is a much bigger hammer than needed, and could result in subtle performance issues. [1]https://lkml.kernel.org/20241219212437.2714151-1-yosryahmed@google.com/ [2]https://lkml.kernel.org/20250107074724.1756696-2-yosryahmed@google.com/ [3]https://lkml.kernel.org/20250107222236.2715883-2-yosryahmed@google.com/ Fixes: 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") Cc: <stable(a)vger.kernel.org> Signed-off-by: Yosry Ahmed <yosryahmed(a)google.com> Reported-by: Johannes Weiner <hannes(a)cmpxchg.org> Closes: https://lore.kernel.org/lkml/20241113213007.GB1564047@cmpxchg.org/ Reported-by: Sam Sun <samsun1006219(a)gmail.com> Closes: https://lore.kernel.org/lkml/CAEkJfYMtSdM5HceNsXUDf5haghD5+o2e7Qv4OcuruL4tP… --- This applies on top of the latest mm-hotfixes-unstable on top of 'Revert "mm: zswap: fix race between [de]compression and CPU hotunplug"' and after 'mm: zswap: disable migration while using per-CPU acomp_ctx' was dropped. v1 -> v2: - Move the initialization of the mutex to pool initialization. - Use the mutex to also synchronize with the CPU hotplug callback (i.e. zswap_cpu_comp_prep()). - Naming cleanups. --- mm/zswap.c | 60 +++++++++++++++++++++++++++++++++++++++++------------- 1 file changed, 46 insertions(+), 14 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index f6316b66fb236..4d7e564732267 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -251,7 +251,7 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor) struct zswap_pool *pool; char name[38]; /* 'zswap' + 32 char (max) num + \0 */ gfp_t gfp = __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; - int ret; + int ret, cpu; if (!zswap_has_pool) { /* if either are unset, pool initialization failed, and we @@ -285,6 +285,9 @@ static struct zswap_pool *zswap_pool_create(char *type, char *compressor) goto error; } + for_each_possible_cpu(cpu) + mutex_init(&per_cpu_ptr(pool->acomp_ctx, cpu)->mutex); + ret = cpuhp_state_add_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node); if (ret) @@ -821,11 +824,12 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) struct acomp_req *req; int ret; - mutex_init(&acomp_ctx->mutex); - + mutex_lock(&acomp_ctx->mutex); acomp_ctx->buffer = kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node(cpu)); - if (!acomp_ctx->buffer) - return -ENOMEM; + if (!acomp_ctx->buffer) { + ret = -ENOMEM; + goto buffer_fail; + } acomp = crypto_alloc_acomp_node(pool->tfm_name, 0, 0, cpu_to_node(cpu)); if (IS_ERR(acomp)) { @@ -844,6 +848,8 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) ret = -ENOMEM; goto req_fail; } + + /* acomp_ctx->req must be NULL if the acomp_ctx is not fully initialized */ acomp_ctx->req = req; crypto_init_wait(&acomp_ctx->wait); @@ -855,12 +861,15 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *node) acomp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, crypto_req_done, &acomp_ctx->wait); + mutex_unlock(&acomp_ctx->mutex); return 0; req_fail: crypto_free_acomp(acomp_ctx->acomp); acomp_fail: kfree(acomp_ctx->buffer); +buffer_fail: + mutex_unlock(&acomp_ctx->mutex); return ret; } @@ -869,17 +878,45 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu); + mutex_lock(&acomp_ctx->mutex); if (!IS_ERR_OR_NULL(acomp_ctx)) { if (!IS_ERR_OR_NULL(acomp_ctx->req)) acomp_request_free(acomp_ctx->req); + acomp_ctx->req = NULL; if (!IS_ERR_OR_NULL(acomp_ctx->acomp)) crypto_free_acomp(acomp_ctx->acomp); kfree(acomp_ctx->buffer); } + mutex_unlock(&acomp_ctx->mutex); return 0; } +static struct crypto_acomp_ctx *acomp_ctx_get_cpu_lock(struct zswap_pool *pool) +{ + struct crypto_acomp_ctx *acomp_ctx; + + for (;;) { + acomp_ctx = raw_cpu_ptr(pool->acomp_ctx); + mutex_lock(&acomp_ctx->mutex); + if (likely(acomp_ctx->req)) + return acomp_ctx; + /* + * It is possible that we were migrated to a different CPU after + * getting the per-CPU ctx but before the mutex was acquired. If + * the old CPU got offlined, zswap_cpu_comp_dead() could have + * already freed ctx->req (among other things) and set it to + * NULL. Just try again on the new CPU that we ended up on. + */ + mutex_unlock(&acomp_ctx->mutex); + } +} + +static void acomp_ctx_put_unlock(struct crypto_acomp_ctx *acomp_ctx) +{ + mutex_unlock(&acomp_ctx->mutex); +} + static bool zswap_compress(struct page *page, struct zswap_entry *entry, struct zswap_pool *pool) { @@ -893,10 +930,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, gfp_t gfp; u8 *dst; - acomp_ctx = raw_cpu_ptr(pool->acomp_ctx); - - mutex_lock(&acomp_ctx->mutex); - + acomp_ctx = acomp_ctx_get_cpu_lock(pool); dst = acomp_ctx->buffer; sg_init_table(&input, 1); sg_set_page(&input, page, PAGE_SIZE, 0); @@ -949,7 +983,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, else if (alloc_ret) zswap_reject_alloc_fail++; - mutex_unlock(&acomp_ctx->mutex); + acomp_ctx_put_unlock(acomp_ctx); return comp_ret == 0 && alloc_ret == 0; } @@ -960,9 +994,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) struct crypto_acomp_ctx *acomp_ctx; u8 *src; - acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); - mutex_lock(&acomp_ctx->mutex); - + acomp_ctx = acomp_ctx_get_cpu_lock(entry->pool); src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO); /* * If zpool_map_handle is atomic, we cannot reliably utilize its mapped buffer @@ -986,10 +1018,10 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, PAGE_SIZE); BUG_ON(crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait)); BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE); - mutex_unlock(&acomp_ctx->mutex); if (src != acomp_ctx->buffer) zpool_unmap_handle(zpool, entry->handle); + acomp_ctx_put_unlock(acomp_ctx); } /********************************* -- 2.47.1.613.gc27f4b7a9f-goog

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[PATCH] mm: zswap: properly synchronize freeing resources during CPU hotunplug

by Yosry Ahmed

In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the current CPU at the beginning of the operation is retrieved and used throughout. However, since neither preemption nor migration are disabled, it is possible that the operation continues on a different CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as some of the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead(). The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when the switch to the crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was retrieved using get_cpu_ptr() which disables preemption and makes sure the CPU cannot go away from under us. Preemption cannot be disabled with the crypto_acomp API as a sleepable context is needed. During CPU hotunplug, hold the acomp_ctx.mutex before freeing any resources, and set acomp_ctx.req to NULL when it is freed. In the compress/decompress paths, after acquiring the acomp_ctx.mutex make sure that acomp_ctx.req is not NULL (i.e. acomp_ctx resources were not freed by CPU hotunplug). Otherwise, retry with the acomp_ctx from the new CPU. This adds proper synchronization to ensure that the acomp_ctx resources are not freed from under compress/decompress paths. Note that the per-CPU acomp_ctx itself (including the mutex) is not freed during CPU hotunplug, only acomp_ctx.req, acomp_ctx.buffer, and acomp_ctx.acomp. So it is safe to acquire the acomp_ctx.mutex of a CPU after it is hotunplugged. Previously a fix was attempted by holding cpus_read_lock() [1]. This would have caused a potential deadlock as it is possible for code already holding the lock to fall into reclaim and enter zswap (causing a deadlock). A fix was also attempted using SRCU for synchronization, but Johannes pointed out that synchronize_srcu() cannot be used in CPU hotplug notifiers [2]. Alternative fixes that were considered/attempted and could have worked: - Refcounting the per-CPU acomp_ctx. This involves complexity in handling the race between the refcount dropping to zero in zswap_[de]compress() and the refcount being re-initialized when the CPU is onlined. - Disabling migration before getting the per-CPU acomp_ctx [3], but that's discouraged and is a much bigger hammer than needed, and could result in subtle performance issues. [1]https://lkml.kernel.org/20241219212437.2714151-1-yosryahmed@google.com/ [2]https://lkml.kernel.org/20250107074724.1756696-2-yosryahmed@google.com/ [3]https://lkml.kernel.org/20250107222236.2715883-2-yosryahmed@google.com/ Fixes: 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") Cc: <stable(a)vger.kernel.org> Signed-off-by: Yosry Ahmed <yosryahmed(a)google.com> Reported-by: Johannes Weiner <hannes(a)cmpxchg.org> Closes: https://lore.kernel.org/lkml/20241113213007.GB1564047@cmpxchg.org/ Reported-by: Sam Sun <samsun1006219(a)gmail.com> Closes: https://lore.kernel.org/lkml/CAEkJfYMtSdM5HceNsXUDf5haghD5+o2e7Qv4OcuruL4tP… --- This applies on top of the latest mm-hotfixes-unstable on top of 'Revert "mm: zswap: fix race between [de]compression and CPU hotunplug"' and after 'mm: zswap: disable migration while using per-CPU acomp_ctx' was dropped. --- mm/zswap.c | 42 +++++++++++++++++++++++++++++++++--------- 1 file changed, 33 insertions(+), 9 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index f6316b66fb236..4e3148050e093 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -869,17 +869,46 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) struct zswap_pool *pool = hlist_entry(node, struct zswap_pool, node); struct crypto_acomp_ctx *acomp_ctx = per_cpu_ptr(pool->acomp_ctx, cpu); + mutex_lock(&acomp_ctx->mutex); if (!IS_ERR_OR_NULL(acomp_ctx)) { if (!IS_ERR_OR_NULL(acomp_ctx->req)) acomp_request_free(acomp_ctx->req); + acomp_ctx->req = NULL; if (!IS_ERR_OR_NULL(acomp_ctx->acomp)) crypto_free_acomp(acomp_ctx->acomp); kfree(acomp_ctx->buffer); } + mutex_unlock(&acomp_ctx->mutex); return 0; } +static struct crypto_acomp_ctx *acomp_ctx_get_cpu_lock( + struct crypto_acomp_ctx __percpu *acomp_ctx) +{ + struct crypto_acomp_ctx *ctx; + + for (;;) { + ctx = raw_cpu_ptr(acomp_ctx); + mutex_lock(&ctx->mutex); + if (likely(ctx->req)) + return ctx; + /* + * It is possible that we were migrated to a different CPU after + * getting the per-CPU ctx but before the mutex was acquired. If + * the old CPU got offlined, zswap_cpu_comp_dead() could have + * already freed ctx->req (among other things) and set it to + * NULL. Just try again on the new CPU that we ended up on. + */ + mutex_unlock(&ctx->mutex); + } +} + +static void acomp_ctx_put_unlock(struct crypto_acomp_ctx *ctx) +{ + mutex_unlock(&ctx->mutex); +} + static bool zswap_compress(struct page *page, struct zswap_entry *entry, struct zswap_pool *pool) { @@ -893,10 +922,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, gfp_t gfp; u8 *dst; - acomp_ctx = raw_cpu_ptr(pool->acomp_ctx); - - mutex_lock(&acomp_ctx->mutex); - + acomp_ctx = acomp_ctx_get_cpu_lock(pool->acomp_ctx); dst = acomp_ctx->buffer; sg_init_table(&input, 1); sg_set_page(&input, page, PAGE_SIZE, 0); @@ -949,7 +975,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, else if (alloc_ret) zswap_reject_alloc_fail++; - mutex_unlock(&acomp_ctx->mutex); + acomp_ctx_put_unlock(acomp_ctx); return comp_ret == 0 && alloc_ret == 0; } @@ -960,9 +986,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) struct crypto_acomp_ctx *acomp_ctx; u8 *src; - acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); - mutex_lock(&acomp_ctx->mutex); - + acomp_ctx = acomp_ctx_get_cpu_lock(entry->pool->acomp_ctx); src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO); /* * If zpool_map_handle is atomic, we cannot reliably utilize its mapped buffer @@ -986,10 +1010,10 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, PAGE_SIZE); BUG_ON(crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &acomp_ctx->wait)); BUG_ON(acomp_ctx->req->dlen != PAGE_SIZE); - mutex_unlock(&acomp_ctx->mutex); if (src != acomp_ctx->buffer) zpool_unmap_handle(zpool, entry->handle); + acomp_ctx_put_unlock(acomp_ctx); } /********************************* -- 2.47.1.613.gc27f4b7a9f-goog

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[PATCH 6.6.y 1/2] erofs: handle overlapped pclusters out of crafted images properly

by Gao Xiang

commit 9e2f9d34dd12e6e5b244ec488bcebd0c2d566c50 upstream. syzbot reported a task hang issue due to a deadlock case where it is waiting for the folio lock of a cached folio that will be used for cache I/Os. After looking into the crafted fuzzed image, I found it's formed with several overlapped big pclusters as below: Ext: logical offset | length : physical offset | length 0: 0.. 16384 | 16384 : 151552.. 167936 | 16384 1: 16384.. 32768 | 16384 : 155648.. 172032 | 16384 2: 32768.. 49152 | 16384 : 537223168.. 537239552 | 16384 ... Here, extent 0/1 are physically overlapped although it's entirely _impossible_ for normal filesystem images generated by mkfs. First, managed folios containing compressed data will be marked as up-to-date and then unlocked immediately (unlike in-place folios) when compressed I/Os are complete. If physical blocks are not submitted in the incremental order, there should be separate BIOs to avoid dependency issues. However, the current code mis-arranges z_erofs_fill_bio_vec() and BIO submission which causes unexpected BIO waits. Second, managed folios will be connected to their own pclusters for efficient inter-queries. However, this is somewhat hard to implement easily if overlapped big pclusters exist. Again, these only appear in fuzzed images so let's simply fall back to temporary short-lived pages for correctness. Additionally, it justifies that referenced managed folios cannot be truncated for now and reverts part of commit 2080ca1ed3e4 ("erofs: tidy up `struct z_erofs_bvec`") for simplicity although it shouldn't be any difference. Reported-by: syzbot+4fc98ed414ae63d1ada2(a)syzkaller.appspotmail.com Reported-by: syzbot+de04e06b28cfecf2281c(a)syzkaller.appspotmail.com Reported-by: syzbot+c8c8238b394be4a1087d(a)syzkaller.appspotmail.com Tested-by: syzbot+4fc98ed414ae63d1ada2(a)syzkaller.appspotmail.com Closes: https://lore.kernel.org/r/0000000000002fda01061e334873@google.com Fixes: 8e6c8fa9f2e9 ("erofs: enable big pcluster feature") Link: https://lore.kernel.org/r/20240910070847.3356592-1-hsiangkao@linux.alibaba.… Signed-off-by: Gao Xiang <hsiangkao(a)linux.alibaba.com> --- fs/erofs/zdata.c | 59 +++++++++++++++++++++++++----------------------- 1 file changed, 31 insertions(+), 28 deletions(-) diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 1c0e6167d8e7..9fa07436a4da 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -1483,14 +1483,13 @@ static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl, goto out; lock_page(page); - - /* only true if page reclaim goes wrong, should never happen */ - DBG_BUGON(justfound && PagePrivate(page)); - - /* the page is still in manage cache */ - if (page->mapping == mc) { + if (likely(page->mapping == mc)) { WRITE_ONCE(pcl->compressed_bvecs[nr].page, page); + /* + * The cached folio is still in managed cache but without + * a valid `->private` pcluster hint. Let's reconnect them. + */ if (!PagePrivate(page)) { /* * impossible to be !PagePrivate(page) for @@ -1504,22 +1503,24 @@ static struct page *pickup_page_for_submission(struct z_erofs_pcluster *pcl, SetPagePrivate(page); } - /* no need to submit io if it is already up-to-date */ - if (PageUptodate(page)) { - unlock_page(page); - page = NULL; + if (likely(page->private == (unsigned long)pcl)) { + /* don't submit cache I/Os again if already uptodate */ + if (PageUptodate(page)) { + unlock_page(page); + page = NULL; + + } + goto out; } - goto out; + /* + * Already linked with another pcluster, which only appears in + * crafted images by fuzzers for now. But handle this anyway. + */ + tocache = false; /* use temporary short-lived pages */ + } else { + DBG_BUGON(1); /* referenced managed folios can't be truncated */ + tocache = true; } - - /* - * the managed page has been truncated, it's unsafe to - * reuse this one, let's allocate a new cache-managed page. - */ - DBG_BUGON(page->mapping); - DBG_BUGON(!justfound); - - tocache = true; unlock_page(page); put_page(page); out_allocpage: @@ -1677,16 +1678,11 @@ static void z_erofs_submit_queue(struct z_erofs_decompress_frontend *f, end = cur + pcl->pclusterpages; do { - struct page *page; - - page = pickup_page_for_submission(pcl, i++, - &f->pagepool, mc); - if (!page) - continue; + struct page *page = NULL; if (bio && (cur != last_index + 1 || last_bdev != mdev.m_bdev)) { -submit_bio_retry: +drain_io: submit_bio(bio); if (memstall) { psi_memstall_leave(&pflags); @@ -1695,6 +1691,13 @@ static void z_erofs_submit_queue(struct z_erofs_decompress_frontend *f, bio = NULL; } + if (!page) { + page = pickup_page_for_submission(pcl, i++, + &f->pagepool, mc); + if (!page) + continue; + } + if (unlikely(PageWorkingset(page)) && !memstall) { psi_memstall_enter(&pflags); memstall = 1; @@ -1715,7 +1718,7 @@ static void z_erofs_submit_queue(struct z_erofs_decompress_frontend *f, } if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) - goto submit_bio_retry; + goto drain_io; last_index = cur; bypass = false; -- 2.43.5

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[PATCH 5.10-6.1] ceph: give up on paths longer than PATH_MAX

by Ilya Dryomov

From: Max Kellermann <max.kellermann(a)ionos.com> commit 550f7ca98ee028a606aa75705a7e77b1bd11720f upstream. If the full path to be built by ceph_mdsc_build_path() happens to be longer than PATH_MAX, then this function will enter an endless (retry) loop, effectively blocking the whole task. Most of the machine becomes unusable, making this a very simple and effective DoS vulnerability. I cannot imagine why this retry was ever implemented, but it seems rather useless and harmful to me. Let's remove it and fail with ENAMETOOLONG instead. Cc: stable(a)vger.kernel.org Reported-by: Dario Weißer <dario(a)cure53.de> Signed-off-by: Max Kellermann <max.kellermann(a)ionos.com> Reviewed-by: Alex Markuze <amarkuze(a)redhat.com> Signed-off-by: Ilya Dryomov <idryomov(a)gmail.com> [idryomov(a)gmail.com: backport to 6.1: pr_warn() is still in use] --- fs/ceph/mds_client.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c index da9fcf48ab6c..741ca7d10032 100644 --- a/fs/ceph/mds_client.c +++ b/fs/ceph/mds_client.c @@ -2447,12 +2447,11 @@ char *ceph_mdsc_build_path(struct dentry *dentry, int *plen, u64 *pbase, if (pos < 0) { /* - * A rename didn't occur, but somehow we didn't end up where - * we thought we would. Throw a warning and try again. + * The path is longer than PATH_MAX and this function + * cannot ever succeed. Creating paths that long is + * possible with Ceph, but Linux cannot use them. */ - pr_warn("build_path did not end path lookup where " - "expected, pos is %d\n", pos); - goto retry; + return ERR_PTR(-ENAMETOOLONG); } *pbase = base; -- 2.46.1

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[PATCH net] netdev: prevent accessing NAPI instances from another namespace

by Jakub Kicinski

The NAPI IDs were not fully exposed to user space prior to the netlink API, so they were never namespaced. The netlink API must ensure that at the very least NAPI instance belongs to the same netns as the owner of the genl sock. napi_by_id() can become static now, but it needs to move because of dev_get_by_napi_id(). Cc: stable(a)vger.kernel.org Fixes: 1287c1ae0fc2 ("netdev-genl: Support setting per-NAPI config values") Fixes: 27f91aaf49b3 ("netdev-genl: Add netlink framework functions for napi") Signed-off-by: Jakub Kicinski <kuba(a)kernel.org> --- Splitting this into fix per-version is a bit tricky, because we need to replace the napi_by_id() helper with a better one. I'll send the stable versions manually. CC: jdamato(a)fastly.com CC: almasrymina(a)google.com CC: amritha.nambiar(a)intel.com CC: sridhar.samudrala(a)intel.com --- net/core/dev.c | 43 +++++++++++++++++++++++++++++------------- net/core/dev.h | 3 ++- net/core/netdev-genl.c | 6 ++---- 3 files changed, 34 insertions(+), 18 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 7c63d97b13c1..e001df4cb486 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -753,6 +753,36 @@ int dev_fill_forward_path(const struct net_device *dev, const u8 *daddr, } EXPORT_SYMBOL_GPL(dev_fill_forward_path); +/* must be called under rcu_read_lock(), as we dont take a reference */ +static struct napi_struct *napi_by_id(unsigned int napi_id) +{ + unsigned int hash = napi_id % HASH_SIZE(napi_hash); + struct napi_struct *napi; + + hlist_for_each_entry_rcu(napi, &napi_hash[hash], napi_hash_node) + if (napi->napi_id == napi_id) + return napi; + + return NULL; +} + +/* must be called under rcu_read_lock(), as we dont take a reference */ +struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id) +{ + struct napi_struct *napi; + + napi = napi_by_id(napi_id); + if (!napi) + return NULL; + + if (WARN_ON_ONCE(!napi->dev)) + return NULL; + if (!net_eq(net, dev_net(napi->dev))) + return NULL; + + return napi; +} + /** * __dev_get_by_name - find a device by its name * @net: the applicable net namespace @@ -6293,19 +6323,6 @@ bool napi_complete_done(struct napi_struct *n, int work_done) } EXPORT_SYMBOL(napi_complete_done); -/* must be called under rcu_read_lock(), as we dont take a reference */ -struct napi_struct *napi_by_id(unsigned int napi_id) -{ - unsigned int hash = napi_id % HASH_SIZE(napi_hash); - struct napi_struct *napi; - - hlist_for_each_entry_rcu(napi, &napi_hash[hash], napi_hash_node) - if (napi->napi_id == napi_id) - return napi; - - return NULL; -} - static void skb_defer_free_flush(struct softnet_data *sd) { struct sk_buff *skb, *next; diff --git a/net/core/dev.h b/net/core/dev.h index aa91eed55a40..08812a025a9b 100644 --- a/net/core/dev.h +++ b/net/core/dev.h @@ -22,6 +22,8 @@ struct sd_flow_limit { extern int netdev_flow_limit_table_len; +struct napi_struct *netdev_napi_by_id(struct net *net, unsigned int napi_id); + #ifdef CONFIG_PROC_FS int __init dev_proc_init(void); #else @@ -269,7 +271,6 @@ void xdp_do_check_flushed(struct napi_struct *napi); static inline void xdp_do_check_flushed(struct napi_struct *napi) { } #endif -struct napi_struct *napi_by_id(unsigned int napi_id); void kick_defer_list_purge(struct softnet_data *sd, unsigned int cpu); #define XMIT_RECURSION_LIMIT 8 diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c index 125b660004d3..a3bdaf075b6b 100644 --- a/net/core/netdev-genl.c +++ b/net/core/netdev-genl.c @@ -167,8 +167,6 @@ netdev_nl_napi_fill_one(struct sk_buff *rsp, struct napi_struct *napi, void *hdr; pid_t pid; - if (WARN_ON_ONCE(!napi->dev)) - return -EINVAL; if (!(napi->dev->flags & IFF_UP)) return 0; @@ -234,7 +232,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info) rtnl_lock(); rcu_read_lock(); - napi = napi_by_id(napi_id); + napi = netdev_napi_by_id(genl_info_net(info), napi_id); if (napi) { err = netdev_nl_napi_fill_one(rsp, napi, info); } else { @@ -355,7 +353,7 @@ int netdev_nl_napi_set_doit(struct sk_buff *skb, struct genl_info *info) rtnl_lock(); rcu_read_lock(); - napi = napi_by_id(napi_id); + napi = netdev_napi_by_id(genl_info_net(info), napi_id); if (napi) { err = netdev_nl_napi_set_config(napi, info); } else { -- 2.47.1

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[PATCH v5 0/5] arm64: Support 2024 dpISA extensions

by Mark Brown

The 2024 architecture release includes a number of data processing extensions, mostly SVE and SME additions with a few others. These are all very straightforward extensions which add instructions but no architectural state so only need hwcaps and exposing of the ID registers to KVM guests and userspace. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v5: - Rebase onto arm64/for-next/cpufeature, which incorporates most of the sysreg updates from earlier versions. - Remove SF8MM8 and SF8MM4 register defintitions which were removed from the ISA in the 2024-12 XML release, along with their associated hwcaps. - Incorporate Marc's fix for SVE hwcaps on SME only systems and update the hwcaps for the newly added features to follow the same pattern. - Link to v4: https://lore.kernel.org/r/20241211-arm64-2024-dpisa-v4-0-0fd403876df2@kerne… Changes in v4: - Fix encodings for ID_AA64ISAR3_EL1. - Link to v3: https://lore.kernel.org/r/20241203-arm64-2024-dpisa-v3-0-a6c78b1aa297@kerne… Changes in v3: - Commit log update for the hwcap test. - Link to v2: https://lore.kernel.org/r/20241030-arm64-2024-dpisa-v2-0-b6601a15d2a5@kerne… Changes in v2: - Filter KVM guest visible bitfields in ID_AA64ISAR3_EL1 to only those we make writeable. - Link to v1: https://lore.kernel.org/r/20241028-arm64-2024-dpisa-v1-0-a38d08b008a8@kerne… --- Marc Zyngier (1): arm64: Filter out SVE hwcaps when FEAT_SVE isn't implemented Mark Brown (4): arm64/sysreg: Update ID_AA64SMFR0_EL1 to DDI0601 2024-12 arm64/hwcap: Describe 2024 dpISA extensions to userspace KVM: arm64: Allow control of dpISA extensions in ID_AA64ISAR3_EL1 kselftest/arm64: Add 2024 dpISA extensions to hwcap test Documentation/arch/arm64/elf_hwcaps.rst | 89 +++++++++-- arch/arm64/include/asm/hwcap.h | 15 ++ arch/arm64/include/uapi/asm/hwcap.h | 15 ++ arch/arm64/kernel/cpufeature.c | 71 +++++++-- arch/arm64/kernel/cpuinfo.c | 15 ++ arch/arm64/kvm/sys_regs.c | 6 +- arch/arm64/tools/sysreg | 26 +++- tools/testing/selftests/arm64/abi/hwcap.c | 235 +++++++++++++++++++++++++++++- 8 files changed, 441 insertions(+), 31 deletions(-) --- base-commit: d66e21d59ed0e043e68ef8c6541c1e9f1a962614 change-id: 20241008-arm64-2024-dpisa-8091074a7f48 Best regards, -- Mark Brown <broonie(a)kernel.org>

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[PATCH v3] arm64/sme: Move storage of reg_smidr to __cpuinfo_store_cpu()

by Mark Brown

In commit 892f7237b3ff ("arm64: Delay initialisation of cpuinfo_arm64::reg_{zcr,smcr}") we moved access to ZCR, SMCR and SMIDR later in the boot process in order to ensure that we don't attempt to interact with them if SVE or SME is disabled on the command line. Unfortunately when initialising the boot CPU in init_cpu_features() we work on a copy of the struct cpuinfo_arm64 for the boot CPU used only during boot, not the percpu copy used by the sysfs code. The expectation of the feature identification code was that the ID registers would be read in __cpuinfo_store_cpu() and the values not modified by init_cpu_features(). The main reason for the original change was to avoid early accesses to ZCR on practical systems that were seen shipping with SVE reported in ID registers but traps enabled at EL3 and handled as fatal errors, SME was rolled in due to the similarity with SVE. Since then we have removed the early accesses to ZCR and SMCR in commits: abef0695f9665c3d ("arm64/sve: Remove ZCR pseudo register from cpufeature code") 391208485c3ad50f ("arm64/sve: Remove SMCR pseudo register from cpufeature code") so only the SMIDR_EL1 part of the change remains. Since SMIDR_EL1 is only trapped via FEAT_IDST and not the SME trap it is less likely to be affected by similar issues, and the factors that lead to issues with SVE are less likely to apply to SME. Since we have not yet seen practical SME systems that need to use a command line override (and are only just beginning to see SME systems at all) and the ID register read is much more likely to be safe let's just store SMIDR_EL1 along with all the other ID register reads in __cpuinfo_store_cpu(). This issue wasn't apparent when testing on emulated platforms that do not report values in SMIDR_EL1. Fixes: 892f7237b3ff ("arm64: Delay initialisation of cpuinfo_arm64::reg_{zcr,smcr}") Signed-off-by: Mark Brown <broonie(a)kernel.org> Cc: stable(a)vger.kernel.org --- Changes in v3: - Leave the override in place. - Link to v2: https://lore.kernel.org/r/20241216-arm64-fix-boot-cpu-smidr-v2-1-a99ffba2c3… Changes in v2: - Move the ID register read back to __cpuinfo_store_cpu(). - Remove the command line option for SME ID register override. - Link to v1: https://lore.kernel.org/r/20241214-arm64-fix-boot-cpu-smidr-v1-1-0745c40772… --- arch/arm64/kernel/cpufeature.c | 13 ------------- arch/arm64/kernel/cpuinfo.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 13 deletions(-) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 6ce71f444ed84f9056196bb21bbfac61c9687e30..818aca922ca6066eb4bdf79e153cccb24246c61b 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1167,12 +1167,6 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info) id_aa64pfr1_sme(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1))) { unsigned long cpacr = cpacr_save_enable_kernel_sme(); - /* - * We mask out SMPS since even if the hardware - * supports priorities the kernel does not at present - * and we block access to them. - */ - info->reg_smidr = read_cpuid(SMIDR_EL1) & ~SMIDR_EL1_SMPS; vec_init_vq_map(ARM64_VEC_SME); cpacr_restore(cpacr); @@ -1423,13 +1417,6 @@ void update_cpu_features(int cpu, id_aa64pfr1_sme(read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1))) { unsigned long cpacr = cpacr_save_enable_kernel_sme(); - /* - * We mask out SMPS since even if the hardware - * supports priorities the kernel does not at present - * and we block access to them. - */ - info->reg_smidr = read_cpuid(SMIDR_EL1) & ~SMIDR_EL1_SMPS; - /* Probe vector lengths */ if (!system_capabilities_finalized()) vec_update_vq_map(ARM64_VEC_SME); diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index d79e88fccdfce427507e7a34c5959ce6309cbd12..c45633b5ae233fe78607fce3d623efb28a9f341a 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -482,6 +482,16 @@ static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) if (id_aa64pfr0_mpam(info->reg_id_aa64pfr0)) info->reg_mpamidr = read_cpuid(MPAMIDR_EL1); + if (IS_ENABLED(CONFIG_ARM64_SME) && + id_aa64pfr1_sme(info->reg_id_aa64pfr1)) { + /* + * We mask out SMPS since even if the hardware + * supports priorities the kernel does not at present + * and we block access to them. + */ + info->reg_smidr = read_cpuid(SMIDR_EL1) & ~SMIDR_EL1_SMPS; + } + cpuinfo_detect_icache_policy(info); } --- base-commit: fac04efc5c793dccbd07e2d59af9f90b7fc0dca4 change-id: 20241213-arm64-fix-boot-cpu-smidr-386b8db292b2 Best regards, -- Mark Brown <broonie(a)kernel.org>

1 month

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[PATCH] m68k: Fix VGA I/O defines

by Thomas Zimmermann

Including m86k's <asm/raw_io.h> in vga.h on nommu platforms results in conflicting defines with io_no.h for various I/O macros from the __raw_read and __raw_write families. An example error is In file included from arch/m68k/include/asm/vga.h:12, from include/video/vga.h:22, from include/linux/vgaarb.h:34, from drivers/video/aperture.c:12: >> arch/m68k/include/asm/raw_io.h:39: warning: "__raw_readb" redefined 39 | #define __raw_readb in_8 | In file included from arch/m68k/include/asm/io.h:6, from include/linux/io.h:13, from include/linux/irq.h:20, from include/asm-generic/hardirq.h:17, from ./arch/m68k/include/generated/asm/hardirq.h:1, from include/linux/hardirq.h:11, from include/linux/interrupt.h:11, from include/linux/trace_recursion.h:5, from include/linux/ftrace.h:10, from include/linux/kprobes.h:28, from include/linux/kgdb.h:19, from include/linux/fb.h:6, from drivers/video/aperture.c:5: arch/m68k/include/asm/io_no.h:16: note: this is the location of the previous definition 16 | #define __raw_readb(addr) \ | Include <asm/io.h>, which avoid raw_io.h on nommu platforms. Also change the defined values of some of the read/write symbols in vga.h to __raw_read/__raw_write as the raw_in/raw_out symbols are not generally available. Signed-off-by: Thomas Zimmermann <tzimmermann(a)suse.de> Reported-by: kernel test robot <lkp(a)intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202501071629.DNEswlm8-lkp@intel.com/ Fixes: 5c3f968712ce ("m68k/video: Create <asm/vga.h>") Cc: Geert Uytterhoeven <geert(a)linux-m68k.org> Cc: linux-fbdev(a)vger.kernel.org Cc: dri-devel(a)lists.freedesktop.org Cc: Helge Deller <deller(a)gmx.de> Cc: <stable(a)vger.kernel.org> # v3.5+ --- arch/m68k/include/asm/vga.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/m68k/include/asm/vga.h b/arch/m68k/include/asm/vga.h index 4742e6bc3ab8..cdd414fa8710 100644 --- a/arch/m68k/include/asm/vga.h +++ b/arch/m68k/include/asm/vga.h @@ -9,7 +9,7 @@ */ #ifndef CONFIG_PCI -#include <asm/raw_io.h> +#include <asm/io.h> #include <asm/kmap.h> /* @@ -29,9 +29,9 @@ #define inw_p(port) 0 #define outb_p(port, val) do { } while (0) #define outw(port, val) do { } while (0) -#define readb raw_inb -#define writeb raw_outb -#define writew raw_outw +#define readb __raw_readb +#define writeb __raw_writeb +#define writew __raw_writew #endif /* CONFIG_PCI */ #endif /* _ASM_M68K_VGA_H */ -- 2.47.1

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[PATCH v2 2/2] mm: zswap: disable migration while using per-CPU acomp_ctx

by Yosry Ahmed

In zswap_compress() and zswap_decompress(), the per-CPU acomp_ctx of the current CPU at the beginning of the operation is retrieved and used throughout. However, since neither preemption nor migration are disabled, it is possible that the operation continues on a different CPU. If the original CPU is hotunplugged while the acomp_ctx is still in use, we run into a UAF bug as the resources attached to the acomp_ctx are freed during hotunplug in zswap_cpu_comp_dead(). The problem was introduced in commit 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") when the switch to the crypto_acomp API was made. Prior to that, the per-CPU crypto_comp was retrieved using get_cpu_ptr() which disables preemption and makes sure the CPU cannot go away from under us. Preemption cannot be disabled with the crypto_acomp API as a sleepable context is needed. Commit 8ba2f844f050 ("mm/zswap: change per-cpu mutex and buffer to per-acomp_ctx") increased the UAF surface area by making the per-CPU buffers dynamic, adding yet another resource that can be freed from under zswap compression/decompression by CPU hotunplug. This cannot be fixed by holding cpus_read_lock(), as it is possible for code already holding the lock to fall into reclaim and enter zswap (causing a deadlock). It also cannot be fixed by wrapping the usage of acomp_ctx in an SRCU critical section and using synchronize_srcu() in zswap_cpu_comp_dead(), because synchronize_srcu() is not allowed in CPU-hotplug notifiers (see Documentation/RCU/Design/Requirements/Requirements.rst). This can be fixed by refcounting the acomp_ctx, but it involves complexity in handling the race between the refcount dropping to zero in zswap_[de]compress() and the refcount being re-initialized when the CPU is onlined. Keep things simple for now and just disable migration while using the per-CPU acomp_ctx to block CPU hotunplug until the usage is over. Fixes: 1ec3b5fe6eec ("mm/zswap: move to use crypto_acomp API for hardware acceleration") Cc: <stable(a)vger.kernel.org> Signed-off-by: Yosry Ahmed <yosryahmed(a)google.com> Reported-by: Johannes Weiner <hannes(a)cmpxchg.org> Closes: https://lore.kernel.org/lkml/20241113213007.GB1564047@cmpxchg.org/ Reported-by: Sam Sun <samsun1006219(a)gmail.com> Closes: https://lore.kernel.org/lkml/CAEkJfYMtSdM5HceNsXUDf5haghD5+o2e7Qv4OcuruL4tP… --- mm/zswap.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index f6316b66fb236..ecd86153e8a32 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -880,6 +880,18 @@ static int zswap_cpu_comp_dead(unsigned int cpu, struct hlist_node *node) return 0; } +/* Remain on the CPU while using its acomp_ctx to stop it from going offline */ +static struct crypto_acomp_ctx *acomp_ctx_get_cpu(struct crypto_acomp_ctx __percpu *acomp_ctx) +{ + migrate_disable(); + return raw_cpu_ptr(acomp_ctx); +} + +static void acomp_ctx_put_cpu(void) +{ + migrate_enable(); +} + static bool zswap_compress(struct page *page, struct zswap_entry *entry, struct zswap_pool *pool) { @@ -893,8 +905,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, gfp_t gfp; u8 *dst; - acomp_ctx = raw_cpu_ptr(pool->acomp_ctx); - + acomp_ctx = acomp_ctx_get_cpu(pool->acomp_ctx); mutex_lock(&acomp_ctx->mutex); dst = acomp_ctx->buffer; @@ -950,6 +961,7 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, zswap_reject_alloc_fail++; mutex_unlock(&acomp_ctx->mutex); + acomp_ctx_put_cpu(); return comp_ret == 0 && alloc_ret == 0; } @@ -960,7 +972,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) struct crypto_acomp_ctx *acomp_ctx; u8 *src; - acomp_ctx = raw_cpu_ptr(entry->pool->acomp_ctx); + acomp_ctx = acomp_ctx_get_cpu(entry->pool->acomp_ctx); mutex_lock(&acomp_ctx->mutex); src = zpool_map_handle(zpool, entry->handle, ZPOOL_MM_RO); @@ -990,6 +1002,7 @@ static void zswap_decompress(struct zswap_entry *entry, struct folio *folio) if (src != acomp_ctx->buffer) zpool_unmap_handle(zpool, entry->handle); + acomp_ctx_put_cpu(); } /********************************* -- 2.47.1.613.gc27f4b7a9f-goog

1 month

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[PATCH 1/1] usb: pd: fix the SenderResponseTimer conform to specification

by joswang

From: Jos Wang <joswang(a)lenovo.com> According to the USB PD3 CTS specification (https://usb.org/document-library/ usb-power-delivery-compliance-test-specification-0/ USB_PD3_CTS_Q4_2024_OR.zip), the requirements for tSenderResponse are different in PD2 and PD3 modes, see Table 19 Timing Table & Calculations. For PD2 mode, the tSenderResponse min 24ms and max 30ms; for PD3 mode, the tSenderResponse min 27ms and max 33ms. For the "TEST.PD.PROT.SRC.2 Get_Source_Cap No Request" test item, after receiving the Source_Capabilities Message sent by the UUT, the tester deliberately does not send a Request Message in order to force the SenderResponse timer on the Source UUT to timeout. The Tester checks that a Hard Reset is detected between tSenderResponse min and max，the delay is between the last bit of the GoodCRC Message EOP has been sent and the first bit of Hard Reset SOP has been received. The current code does not distinguish between PD2 and PD3 modes, and tSenderResponse defaults to 60ms. This will cause this test item and the following tests to fail: TEST.PD.PROT.SRC3.2 SenderResponseTimer Timeout TEST.PD.PROT.SNK.6 SenderResponseTimer Timeout Set the SenderResponseTimer timeout to 27ms to meet the PD2 and PD3 mode requirements. Fixes: f0690a25a140 ("staging: typec: USB Type-C Port Manager (tcpm)") Cc: stable(a)vger.kernel.org Signed-off-by: Jos Wang <joswang(a)lenovo.com> --- include/linux/usb/pd.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h index 3068c3084eb6..99ca49bbf376 100644 --- a/include/linux/usb/pd.h +++ b/include/linux/usb/pd.h @@ -475,7 +475,7 @@ static inline unsigned int rdo_max_power(u32 rdo) #define PD_T_NO_RESPONSE 5000 /* 4.5 - 5.5 seconds */ #define PD_T_DB_DETECT 10000 /* 10 - 15 seconds */ #define PD_T_SEND_SOURCE_CAP 150 /* 100 - 200 ms */ -#define PD_T_SENDER_RESPONSE 60 /* 24 - 30 ms, relaxed */ +#define PD_T_SENDER_RESPONSE 27 /* 24 - 30 ms */ #define PD_T_RECEIVER_RESPONSE 15 /* 15ms max */ #define PD_T_SOURCE_ACTIVITY 45 #define PD_T_SINK_ACTIVITY 135 -- 2.17.1

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Linux-stable-mirror January 2025