From e873c74132f0c5f1452816cd9bb26208f0bba1e1 Mon Sep 17 00:00:00 2001 From: Shivank Garg Date: Sat, 22 Aug 2026 19:22:05 +0000 Subject: dmaengine: fix use-after-free in dma_chan_put() and dma_release_channel() When dma_device_put() drops the last reference on chan->device->ref, dma_device_release() runs and may free the dma_device along with its channels. dma_chan_put() then still reads chan->device->owner via dma_chan_to_owner() for the trailing module_put(). KASAN catches it: slab-use-after-free in dma_chan_put+0x3e6/0x4c0 Read of size 8 by task insmod/6319 Freed by task 6319: kfree+0x225/0x470 dma_chan_put+0x395/0x4c0 dmaengine_put+0xf8/0x160 Cache the module owner in dma_chan_put() before the put so the trailing module_put() does not need chan->device. Fixes: 8ad342a86359 ("dmaengine: Add reference counting to dma_device struct") Suggested-by: Sashiko Link: https://sashiko.dev/#/patchset/20260518-dmaengine-kref-fix-v1-1-4d6125048fb7@amd.com Reviewed-by: Frank Li Reviewed-by: Logan Gunthorpe Signed-off-by: Shivank Garg Link: https://patch.msgid.link/20260822-dmaengine-kref-fix-v5-3-d4a4ee47d927@amd.com Signed-off-by: Vinod Koul --- tools/perf/util/expr.l | 150 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 tools/perf/util/expr.l (limited to 'tools/perf/util/expr.l') diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l new file mode 100644 index 000000000..f16ccff27 --- /dev/null +++ b/tools/perf/util/expr.l @@ -0,0 +1,150 @@ +%option prefix="expr_" +%option reentrant +%option bison-bridge + +%{ +#include +#include "expr.h" +#include "expr-bison.h" +#include + +char *expr_get_text(yyscan_t yyscanner); +YYSTYPE *expr_get_lval(yyscan_t yyscanner); + +static double __value(YYSTYPE *yylval, char *str, int token) +{ + double num; + + errno = 0; + num = strtod(str, NULL); + if (errno) + return EXPR_ERROR; + + yylval->num = num; + return token; +} + +static int value(yyscan_t scanner) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + char *text = expr_get_text(scanner); + + return __value(yylval, text, NUMBER); +} + +/* + * Allow @ instead of / to be able to specify pmu/event/ without + * conflicts with normal division. + */ +static char *normalize(char *str, int runtime) +{ + char *ret = str; + char *dst = str; + + while (*str) { + if (*str == '\\') { + *dst++ = *++str; + if (!*str) + break; + } + else if (*str == '?') { + char *paramval; + int i = 0; + int size = asprintf(¶mval, "%d", runtime); + + if (size < 0) + *dst++ = '0'; + else { + while (i < size) + *dst++ = paramval[i++]; + free(paramval); + } + } + else + *dst++ = *str; + str++; + } + + *dst = 0x0; + return ret; +} + +static int str(yyscan_t scanner, int token, int runtime) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + char *text = expr_get_text(scanner); + + yylval->str = normalize(strdup(text), runtime); + if (!yylval->str) + return EXPR_ERROR; + + yylval->str = normalize(yylval->str, runtime); + return token; +} + +static int literal(yyscan_t scanner, const struct expr_scanner_ctx *sctx) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + + yylval->num = expr__get_literal(expr_get_text(scanner), sctx); + if (isnan(yylval->num)) { + if (!sctx->is_test) + return EXPR_ERROR; + yylval->num = 1; + } + return LITERAL; +} + +static int nan_value(yyscan_t scanner) +{ + YYSTYPE *yylval = expr_get_lval(scanner); + + yylval->num = NAN; + return NUMBER; +} +%} + +number ([0-9]+\.?[0-9]*|[0-9]*\.?[0-9]+)(e-?[0-9]+)? + +sch [-,=] +spec \\{sch} +sym [0-9a-zA-Z_\.:@?]+ +symbol ({spec}|{sym})+ +literal #[0-9a-zA-Z_\.\-]+ + +%% + struct expr_scanner_ctx *sctx = expr_get_extra(yyscanner); + +d_ratio { return D_RATIO; } +max { return MAX; } +min { return MIN; } +if { return IF; } +else { return ELSE; } +source_count { return SOURCE_COUNT; } +aggr_nr { return AGGR_NR; } +has_event { return HAS_EVENT; } +strcmp_cpuid_str { return STRCMP_CPUID_STR; } +NaN { return nan_value(yyscanner); } +{literal} { return literal(yyscanner, sctx); } +{number} { return value(yyscanner); } +{symbol} { return str(yyscanner, ID, sctx->runtime); } +"|" { return '|'; } +"^" { return '^'; } +"&" { return '&'; } +"<" { return '<'; } +">" { return '>'; } +"-" { return '-'; } +"+" { return '+'; } +"*" { return '*'; } +"/" { return '/'; } +"%" { return '%'; } +"(" { return '('; } +")" { return ')'; } +"," { return ','; } +. { } +%% + +int expr_wrap(void *scanner __maybe_unused) +{ + return 1; +} -- cgit v1.3.1