From 034dd340b08be1f2f0477ad16131d609f9dbd53c Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 30 Aug 2026 09:22:00 -0700 Subject: Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Fix error output of boot instance creation failure Currently if a boot instance creation fails, instead of printing out the name of the instance that failed, it prints "(null)". That is because it prints "cur_str" that had already been processed by strsep(). Print the saved name instead. While at it, print the error code of the failure. - Fix use-after-free for same named historgrams Histograms can be named so that they can be used in multiple events. But if the named histogram has a variable attached, the second event that uses the named histogram which duplicates it and needs to free the original after duplication leaves the old variable in place and still visible. If another histogram uses than variable, it will use the stale one which will try to reference the freed duplicate histogram and crash the kernel. Free the duplicate variables along with the duplicated histogram data. - Check return value of kthread_run() in event self test The events self tests uses a kthread for testing but does not check if it succeeded in creating a kthread. If the kthread creation were to fail, the code will still try to call kthread_stop() on the error returned. - Fix race between reading trace_pipe and updating subbuffer size If a user is reading the trace_pipe file at the same time they update the ring buffer sub-buffer size, can cause the trace_pipe read to read stale data. Add trace_access_lock() around updating the ring buffer sub-buffer size. - Fix eventfs_inode on failure path in creation of the events directory In the creation of the "events" directory, if after allocating the eventfs_inode a failure is detected, it calls cleanup_ei() which calls free_ei(). The free_ei() will test if eventfs_inode being freed has no children. It is a bug if it does. But on the failure case of the creation of the "events" directory, the children lists have not yet been initialized and the free will trigger a warning because list_empty() on an uninitialized list returns false. Move the initialization into init_ei() where it makes more sense and makes sure that a created eventfs_inode has its lists initialized upon creation. - Check return value of kthread_run() in ftrace direct sample code The sample code that shows how to use the ftrace direct calls does not test the return of kthread_run() to see if it succeeds. Return a failure if the kthread_run() doesn't succeed. - Clear user events state on fork in case of alloc failure On fork, the child gets a pointer to the parent's user events state. It makes a copy of it then updates the child's pointer to it. But if the allocation fails, the duplication function leaves the child with a pointer to its parent's descriptor. When the child cleans up its data, it will free the parent's descriptor while the parent is still using it. In the duplication function, set the child's user_event_mm to NULL before testing if the allocation succeeded, and when it exits it will not free the parent's descriptor. - Fix retry exhaustion in simple ring buffer reader swap simple_ring_buffer_swap_reader_page() starts with retry set to 8 and post-decrements it only after a failed link replacement. On the final attempt, a successful replacement leaves retry at zero, while a failed replacement leaves it at -1. But the check for success expects the retry value to be non-zero and exits with an error on zero. This is the opposite result. Fix it. - Fail nicely when the remote swap_reader_page() returns an error Currently, if the swap_reader_page() of a remote buffer fails, it triggers a WARN_ON_ONCE() and continues normally. Instead, have it exit with an error and a pr_warn() print instead of a full WARNING. * tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: ring-buffer: Stop remote reader update when page swap fails tracing: Fix retry exhaustion in simple ring buffer reader swap tracing/user_events: Clear copied tracing state before fork duplication samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify eventfs: Initialize ei->children and ei->list in init_ei() tracing: Fix use-after-free in trace_pipe read on sub-buffer order change tracing: Fix crash passing ERR_PTR to kthread_stop() tracing: Fix use-after-free with same-name named triggers tracing: Fix logged instance name on creation failure --- fs/hfs/bitmap.c | 243 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 243 insertions(+) create mode 100644 fs/hfs/bitmap.c (limited to 'fs/hfs/bitmap.c') diff --git a/fs/hfs/bitmap.c b/fs/hfs/bitmap.c new file mode 100644 index 000000000..5e84833a4 --- /dev/null +++ b/fs/hfs/bitmap.c @@ -0,0 +1,243 @@ +/* + * linux/fs/hfs/bitmap.c + * + * Copyright (C) 1996-1997 Paul H. Hargrove + * (C) 2003 Ardis Technologies + * This file may be distributed under the terms of the GNU General Public License. + * + * Based on GPLed code Copyright (C) 1995 Michael Dreher + * + * This file contains the code to modify the volume bitmap: + * search/set/clear bits. + */ + +#include "hfs_fs.h" + +/* + * hfs_find_zero_bit() + * + * Description: + * Given a block of memory, its length in bits, and a starting bit number, + * determine the number of the first zero bits (in left-to-right ordering) + * in that range. + * + * Returns >= 'size' if no zero bits are found in the range. + * + * Accesses memory in 32-bit aligned chunks of 32-bits and thus + * may read beyond the 'size'th bit. + */ +static u32 hfs_find_set_zero_bits(__be32 *bitmap, u32 size, u32 offset, u32 *max) +{ + __be32 *curr, *end; + u32 mask, start, len, n; + __be32 val; + int i; + + len = *max; + if (!len) + return size; + + curr = bitmap + (offset / 32); + end = bitmap + ((size + 31) / 32); + + /* scan the first partial u32 for zero bits */ + val = *curr; + if (~val) { + n = be32_to_cpu(val); + i = offset % 32; + mask = (1U << 31) >> i; + for (; i < 32; mask >>= 1, i++) { + if (!(n & mask)) + goto found; + } + } + + /* scan complete u32s for the first zero bit */ + while (++curr < end) { + val = *curr; + if (~val) { + n = be32_to_cpu(val); + mask = 1 << 31; + for (i = 0; i < 32; mask >>= 1, i++) { + if (!(n & mask)) + goto found; + } + } + } + return size; + +found: + start = (curr - bitmap) * 32 + i; + if (start >= size) + return start; + /* do any partial u32 at the start */ + len = min(size - start, len); + while (1) { + n |= mask; + if (++i >= 32) + break; + mask >>= 1; + if (!--len || n & mask) + goto done; + } + if (!--len) + goto done; + *curr++ = cpu_to_be32(n); + /* do full u32s */ + while (1) { + n = be32_to_cpu(*curr); + if (len < 32) + break; + if (n) { + len = 32; + break; + } + *curr++ = cpu_to_be32(0xffffffff); + len -= 32; + } + /* do any partial u32 at end */ + mask = 1U << 31; + for (i = 0; i < len; i++) { + if (n & mask) + break; + n |= mask; + mask >>= 1; + } +done: + *curr = cpu_to_be32(n); + *max = (curr - bitmap) * 32 + i - start; + return start; +} + +/* + * hfs_vbm_search_free() + * + * Description: + * Search for 'num_bits' consecutive cleared bits in the bitmap blocks of + * the hfs MDB. 'mdb' had better be locked or the returned range + * may be no longer free, when this functions returns! + * XXX Currently the search starts from bit 0, but it should start with + * the bit number stored in 's_alloc_ptr' of the MDB. + * Input Variable(s): + * struct hfs_mdb *mdb: Pointer to the hfs MDB + * u16 *num_bits: Pointer to the number of cleared bits + * to search for + * Output Variable(s): + * u16 *num_bits: The number of consecutive clear bits of the + * returned range. If the bitmap is fragmented, this will be less than + * requested and it will be zero, when the disk is full. + * Returns: + * The number of the first bit of the range of cleared bits which has been + * found. When 'num_bits' is zero, this is invalid! + * Preconditions: + * 'mdb' points to a "valid" (struct hfs_mdb). + * 'num_bits' points to a variable of type (u16), which contains + * the number of cleared bits to find. + * Postconditions: + * 'num_bits' is set to the length of the found sequence. + */ +u32 hfs_vbm_search_free(struct super_block *sb, u32 goal, u32 *num_bits) +{ + void *bitmap; + u32 pos; + + /* make sure we have actual work to perform */ + if (!*num_bits) + return 0; + + mutex_lock(&HFS_SB(sb)->bitmap_lock); + bitmap = HFS_SB(sb)->bitmap; + + pos = hfs_find_set_zero_bits(bitmap, HFS_SB(sb)->fs_ablocks, goal, num_bits); + if (pos >= HFS_SB(sb)->fs_ablocks) { + if (goal) + pos = hfs_find_set_zero_bits(bitmap, goal, 0, num_bits); + if (pos >= HFS_SB(sb)->fs_ablocks) { + *num_bits = pos = 0; + goto out; + } + } + + hfs_dbg("pos %u, num_bits %u\n", pos, *num_bits); + HFS_SB(sb)->free_ablocks -= *num_bits; + hfs_bitmap_dirty(sb); +out: + mutex_unlock(&HFS_SB(sb)->bitmap_lock); + return pos; +} + + +/* + * hfs_clear_vbm_bits() + * + * Description: + * Clear the requested bits in the volume bitmap of the hfs filesystem + * Input Variable(s): + * struct hfs_mdb *mdb: Pointer to the hfs MDB + * u16 start: The offset of the first bit + * u16 count: The number of bits + * Output Variable(s): + * None + * Returns: + * 0: no error + * -1: One of the bits was already clear. This is a strange + * error and when it happens, the filesystem must be repaired! + * -2: One or more of the bits are out of range of the bitmap. + * Preconditions: + * 'mdb' points to a "valid" (struct hfs_mdb). + * Postconditions: + * Starting with bit number 'start', 'count' bits in the volume bitmap + * are cleared. The affected bitmap blocks are marked "dirty", the free + * block count of the MDB is updated and the MDB is marked dirty. + */ +int hfs_clear_vbm_bits(struct super_block *sb, u16 start, u16 count) +{ + __be32 *curr; + u32 mask; + int i, len; + + /* is there any actual work to be done? */ + if (!count) + return 0; + + hfs_dbg("start %u, count %u\n", start, count); + /* are all of the bits in range? */ + if ((start + count) > HFS_SB(sb)->fs_ablocks) + return -2; + + mutex_lock(&HFS_SB(sb)->bitmap_lock); + /* bitmap is always on a 32-bit boundary */ + curr = HFS_SB(sb)->bitmap + (start / 32); + len = count; + + /* do any partial u32 at the start */ + i = start % 32; + if (i) { + int j = 32 - i; + mask = 0xffffffffU << j; + if (j > count) { + mask |= 0xffffffffU >> (i + count); + *curr &= cpu_to_be32(mask); + goto out; + } + *curr++ &= cpu_to_be32(mask); + count -= j; + } + + /* do full u32s */ + while (count >= 32) { + *curr++ = 0; + count -= 32; + } + /* do any partial u32 at end */ + if (count) { + mask = 0xffffffffU >> count; + *curr &= cpu_to_be32(mask); + } +out: + HFS_SB(sb)->free_ablocks += len; + mutex_unlock(&HFS_SB(sb)->bitmap_lock); + hfs_bitmap_dirty(sb); + + return 0; +} -- cgit v1.3.1