From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- net/ceph/pagevec.c | 101 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 101 insertions(+) create mode 100644 net/ceph/pagevec.c (limited to 'net/ceph/pagevec.c') diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c new file mode 100644 index 000000000..a6aa5b3b7 --- /dev/null +++ b/net/ceph/pagevec.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 +#include + +#include +#include +#include +#include +#include +#include + +#include + +void ceph_release_page_vector(struct page **pages, int num_pages) +{ + int i; + + for (i = 0; i < num_pages; i++) + __free_pages(pages[i], 0); + kfree(pages); +} +EXPORT_SYMBOL(ceph_release_page_vector); + +/* + * allocate a vector new pages + */ +struct page **ceph_alloc_page_vector(int num_pages, gfp_t flags) +{ + struct page **pages; + int i; + + pages = kmalloc_objs(*pages, num_pages, flags); + if (!pages) + return ERR_PTR(-ENOMEM); + for (i = 0; i < num_pages; i++) { + pages[i] = __page_cache_alloc(flags); + if (pages[i] == NULL) { + ceph_release_page_vector(pages, i); + return ERR_PTR(-ENOMEM); + } + } + return pages; +} +EXPORT_SYMBOL(ceph_alloc_page_vector); + +void ceph_copy_from_page_vector(struct page **pages, + void *data, + loff_t off, size_t len) +{ + int i = 0; + size_t po = off & ~PAGE_MASK; + size_t left = len; + + while (left > 0) { + size_t l = min_t(size_t, PAGE_SIZE-po, left); + + memcpy(data, page_address(pages[i]) + po, l); + data += l; + left -= l; + po += l; + if (po == PAGE_SIZE) { + po = 0; + i++; + } + } +} +EXPORT_SYMBOL(ceph_copy_from_page_vector); + +/* + * Zero an extent within a page vector. Offset is relative to the + * start of the first page. + */ +void ceph_zero_page_vector_range(int off, int len, struct page **pages) +{ + int i = off >> PAGE_SHIFT; + + off &= ~PAGE_MASK; + + dout("zero_page_vector_page %u~%u\n", off, len); + + /* leading partial page? */ + if (off) { + int end = min((int)PAGE_SIZE, off + len); + dout("zeroing %d %p head from %d\n", i, pages[i], + (int)off); + zero_user_segment(pages[i], off, end); + len -= (end - off); + i++; + } + while (len >= PAGE_SIZE) { + dout("zeroing %d %p len=%d\n", i, pages[i], len); + zero_user_segment(pages[i], 0, PAGE_SIZE); + len -= PAGE_SIZE; + i++; + } + /* trailing partial page? */ + if (len) { + dout("zeroing %d %p tail to %d\n", i, pages[i], (int)len); + zero_user_segment(pages[i], 0, len); + } +} +EXPORT_SYMBOL(ceph_zero_page_vector_range); -- cgit v1.3.1