kernel/git/stable/linux-stable.git/tools/perf, branch linux-6.6.y

perf dso: Guard against cache underflow on short reads in dso_cache__memcpy()

2026-09-14T11:29:48+00:00

[ Upstream commit 390a9461cd73bdd13acc0f6d763618ae1ff8fa17 ] dso_cache__memcpy() computes cache_offset = offset - cache->offset, then cache_size = min(cache->size - cache_offset, size). The RB tree lookup in __dso_cache__find() matches using the full DSO__DATA_CACHE_SIZE window, but cache->size reflects the actual pread return value from dso_cache__populate(). A short pread (e.g. near end-of-file) makes cache->size smaller than DSO__DATA_CACHE_SIZE. If a subsequent access targets an offset past cache->offset + cache->size but within the DSO__DATA_CACHE_SIZE window, the cache entry is found but cache_offset exceeds cache->size. Since both are u64, the subtraction cache->size - cache_offset wraps to a large value, min() selects the caller's size, and memcpy reads out of bounds. Return 0 for an offset past the valid cached data. For a regular file a short pread only happens at end-of-file, so 0 is what a direct pread() at that offset would return: cached_io() stops its read loop as on EOF. Re-reading from the backing file would not help — a second pread at the same offset returns the same short count. Fixes: 366df72657e0 ("perf dso: Refactor dso_cache__read()") Reported-by: sashiko-bot Reviewed-by: Ian Rogers Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf dso: Guard close() against invalid fd in dso__decompress_kmodule_path()

2026-09-14T11:29:48+00:00

[ Upstream commit 10f452dc2de401be76ae8e7395c9663313df8b53 ] dso__decompress_kmodule_path() unconditionally calls close(fd) on the return value of decompress_kmodule(). When decompression fails or the DSO is not compressed, decompress_kmodule() returns -1. close(-1) fails with EBADF and clobbers errno, which callers up the chain (dso__get_filename → __open_dso) depend on for error propagation. Guard the close() call with fd >= 0 so only valid file descriptors are closed. Fixes: 42b3fa670825 ("perf tools: Introduce dso__decompress_kmodule_{fd,path}") Reported-by: sashiko-bot Reviewed-by: Ian Rogers Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf synthetic-events: Fix divide by zero in perf_event__synthesize_threads

2026-09-14T11:29:41+00:00

[ Upstream commit 16a12a54e9a1151a37aab74914a51b86f7f58d0e ] If scandir() finds no matching tasks in /proc, n is 0. If thread_nr is > 1, we bypass the single-thread fast path and then clamp thread_nr to n, making it 0. This results in a divide by zero when calculating num_per_thread. Handle n <= 1 early to use the single-thread fast path and prevent the crash. Fixes: 340b47f510bb ("perf top: Implement multithreading for perf_event__synthesize_threads") Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf synthetic-events: Fix uninitialized pthread_join

2026-09-14T11:29:41+00:00

[ Upstream commit 54ba44db4dddc4ca06b49bae0f9d6c5861430b18 ] In perf_event__synthesize_threads(), fix an uninitialized pthread_join() call when thread creation fails by only joining the successfully created threads. Assisted-by: Antigravity:gemini-3.1-pro Fixes: 340b47f510bb ("perf top: Implement multithreading for perf_event__synthesize_threads") Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf stat: Fix evsel_list leak in cmd_stat

2026-09-14T11:29:41+00:00

[ Upstream commit 340641a4b5fff4f4b12261c9d92169f6e2ea11f4 ] Fix a memory leak in cmd_stat() where evsel_list is leaked if an error occurs while opening the output file. Assisted-by: Antigravity:gemini-3.1-pro Fixes: 361c99a661a7 ("perf evsel: Introduce perf_evlist") Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf trace-event: Fix integer truncation in do_read() and skip()

2026-09-14T11:29:40+00:00

[ Upstream commit c108c1391be0826920991d24532fbae8f6373ddc ] The do_read() and skip() functions use 'int' for size parameters, truncating 64-bit sizes from callers. This causes two issues: 1. Uninitialized memory dump: do_read() reads fewer bytes than allocated, leaving uninitialized heap memory that gets written to output files. 2. Out-of-bounds read: Parsing functions process the full 64-bit size while only partial data was read into the buffer. Change do_read(), __do_read(), and skip() to use size_t for size parameters and ssize_t for return values (where applicable), matching read()/write() system calls. Update callers to use ssize_t for storing return values. Fixes: 4a31e56599d4 ("perf tools: Get rid of read_or_die() in trace-event-read.c") Signed-off-by: Tanushree Shah Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf trace-event: Fix buffer overflow in read_string()

2026-09-14T11:29:38+00:00

[ Upstream commit 1121a7af1833f8b5723f1e32685b461614353d5d ] read_string() writes into buf[BUFSIZ] one byte at a time without checking 'size' against the buffer bound before each write. A string longer than BUFSIZ in the input overflows the stack buffer. Add a bounds check before each write to prevent overflow. On overflow the function returns NULL, matching its other error paths. Fixes: 9215545e99d8 ("perf: Convert perf tracing data into a tracing_data event") Signed-off-by: Tanushree Shah Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf intel-bts: Fix off-by-one in auxtrace_info minimum size check

2026-09-14T11:29:34+00:00

[ Upstream commit b9fb8225951ce27e62a2235a71f3ab01137aaec3 ] Same pattern as the Intel PT fix: min_sz is set to sizeof(u64) * INTEL_BTS_SNAPSHOT_MODE, but the code accesses auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE], which requires at least INTEL_BTS_SNAPSHOT_MODE + 1 elements. Use (INTEL_BTS_SNAPSHOT_MODE + 1) to ensure the highest accessed index is within bounds. Fixes: d0170af7004dce9c ("perf tools: Add Intel BTS support") Reported-by: sashiko-bot Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Reviewed-by: James Clark Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf intel-pt: Fix off-by-one in auxtrace_info minimum size check

2026-09-14T11:29:34+00:00

[ Upstream commit c4362d5e1a5ed4ce2098798f655a636c4340fa20 ] min_sz is set to sizeof(u64) * INTEL_PT_PER_CPU_MMAPS, but the code accesses auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS], which requires at least INTEL_PT_PER_CPU_MMAPS + 1 elements. A file with exactly min_sz bytes of priv data passes the size check but the access reads one u64 past the validated region. Use (INTEL_PT_PER_CPU_MMAPS + 1) to ensure the highest accessed index is within bounds. Fixes: 90e457f7be087005 ("perf tools: Add Intel PT support") Reported-by: sashiko-bot Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Reviewed-by: James Clark Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf auxtrace: Fix queue grow overflow and old array leak

2026-09-14T11:29:34+00:00

[ Upstream commit 96fcc9ea5f18c083a1fa73da23afef7e953f7dca ] auxtrace_queues__grow() has two bugs: 1. When idx is UINT_MAX, the caller passes new_nr_queues = idx + 1 = 0. The function skips growing (since any nr_queues >= 0), returns success, and the caller accesses queue_array[UINT_MAX] — an OOB heap write. Fix by rejecting new_nr_queues == 0 up front. 2. The function allocates a new queue_array via calloc and copies elements from the old array, but never frees the old array. Fix by saving the old pointer and freeing it after the copy. Fixes: e502789302a6ece9 ("perf auxtrace: Add helpers for queuing AUX area tracing data") Reported-by: sashiko-bot Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Reviewed-by: James Clark Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin