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 --- lib/crypto/mpi/mpi-mul.c | 111 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 111 insertions(+) create mode 100644 lib/crypto/mpi/mpi-mul.c (limited to 'lib/crypto/mpi/mpi-mul.c') diff --git a/lib/crypto/mpi/mpi-mul.c b/lib/crypto/mpi/mpi-mul.c new file mode 100644 index 000000000..d79f186ad --- /dev/null +++ b/lib/crypto/mpi/mpi-mul.c @@ -0,0 +1,111 @@ +/* mpi-mul.c - MPI functions + * Copyright (C) 1994, 1996, 1998, 2001, 2002, + * 2003 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Note: This code is heavily based on the GNU MP Library. + * Actually it's the same code with only minor changes in the + * way the data is stored; this is to support the abstraction + * of an optional secure memory allocation which may be used + * to avoid revealing of sensitive data due to paging etc. + */ + +#include + +#include "mpi-internal.h" + +int mpi_mul(MPI w, MPI u, MPI v) +{ + mpi_size_t usize, vsize, wsize; + mpi_ptr_t up, vp, wp; + mpi_limb_t cy; + int usign, vsign, sign_product; + int assign_wp = 0; + mpi_ptr_t tmp_limb = NULL; + int err = 0; + + if (u->nlimbs < v->nlimbs) { + /* Swap U and V. */ + usize = v->nlimbs; + usign = v->sign; + up = v->d; + vsize = u->nlimbs; + vsign = u->sign; + vp = u->d; + } else { + usize = u->nlimbs; + usign = u->sign; + up = u->d; + vsize = v->nlimbs; + vsign = v->sign; + vp = v->d; + } + sign_product = usign ^ vsign; + wp = w->d; + + /* Ensure W has space enough to store the result. */ + wsize = usize + vsize; + if (w->alloced < wsize) { + if (wp == up || wp == vp) { + wp = mpi_alloc_limb_space(wsize); + if (!wp) + return -ENOMEM; + assign_wp = 1; + } else { + err = mpi_resize(w, wsize); + if (err) + return err; + wp = w->d; + } + } else { /* Make U and V not overlap with W. */ + if (wp == up) { + /* W and U are identical. Allocate temporary space for U. */ + up = tmp_limb = mpi_alloc_limb_space(usize); + if (!up) + return -ENOMEM; + /* Is V identical too? Keep it identical with U. */ + if (wp == vp) + vp = up; + /* Copy to the temporary space. */ + MPN_COPY(up, wp, usize); + } else if (wp == vp) { + /* W and V are identical. Allocate temporary space for V. */ + vp = tmp_limb = mpi_alloc_limb_space(vsize); + if (!vp) + return -ENOMEM; + /* Copy to the temporary space. */ + MPN_COPY(vp, wp, vsize); + } + } + + if (!vsize) + wsize = 0; + else { + err = mpihelp_mul(wp, up, usize, vp, vsize, &cy); + if (err) { + if (assign_wp) + mpi_free_limb_space(wp); + goto free_tmp_limb; + } + wsize -= cy ? 0:1; + } + + if (assign_wp) + mpi_assign_limb_space(w, wp, wsize); + w->nlimbs = wsize; + w->sign = sign_product; + +free_tmp_limb: + if (tmp_limb) + mpi_free_limb_space(tmp_limb); + return err; +} +EXPORT_SYMBOL_GPL(mpi_mul); + +int mpi_mulm(MPI w, MPI u, MPI v, MPI m) +{ + return mpi_mul(w, u, v) ?: + mpi_tdiv_r(w, w, m); +} +EXPORT_SYMBOL_GPL(mpi_mulm); -- cgit v1.3.1