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=?ISO-8859-1?Q?Wei=DFschuh?= Cc: linux-kernel@vger.kernel.org, linux-next@vger.kernel.org, Thomas Gleixner , spasswolf@web.de Date: Wed, 09 Jul 2025 18:40:15 +0200 In-Reply-To: <20250709150929-7198f921-5b85-461a-acc1-ccc04e9adbab@linutronix.de> References: <20250701-vdso-auxclock-v1-6-df7d9f87b9b8@linutronix.de> <20250709124216.3011-1-spasswolf@web.de> <20250709150929-7198f921-5b85-461a-acc1-ccc04e9adbab@linutronix.de> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.56.1-1 Precedence: bulk X-Mailing-List: linux-next@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:LRUCica14rnjwQi3ccJDnfNh+Oi67b8+gqM2L0T96nGSRX2H7hk d1Q1Fx/9L0VzCVQdMLJzYU7N/4nkNdd/h3ynZIjq3K6rID7+HjH9hpgVEWapKK7eH8HKUJJ SNmTBJRMhJ7VrNxH5SsMaHh75IXg0tAx0IFeRLkemKZiIocaoTX+C+InrjWv5EZAbpWC6Mj jrQReJWzi/ruWM3IWza2Q== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:PlZp/GoHIGg=;oxW5ucQV2sTX4ASO7DX/pVvvWw2 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ey12PVNQyKgoQBCm+u8Yd1jBzqzZ/mr0zvvqbGq5k0pO3giMWB05G4G1QrUGOYoHZNreClf0u 26wjyTe4I7n0wSMSbWij66Jd9c8juNYJZLgWKTNxSuyLnVsZrCFBpo/Bc5J8DfarO0r45/8Ym rDy9iBvZgHHejzaM2kf11oMsciMU+Eq9MdtmO6kyAdAAM13QY7N+2dlcoRZF5pFRRd/Vqu6uk ZvxEiocXGc6PIP9iMKPA6zfSFkobvmrJaLuhWJjLJjlJYeJLlOsVssmTOrEhu2rINola+oeYm cN5akS6bbUhXHe1yvVHB1zqOGVzVxKmtD4I7DNmndNk9UXQm5tiP6PYxKpr7UOqVMaXs3J4ot YOUJQg/ZeVki86OuQTcgMM+/6sJmiCWnTd//KwG55MAQsKd97y18sqneC8KvCYXbXBkr81ghl +/l/mLnM6WyoYySYEfb1nYbDyL5vxJJcNkA0oRIbfJi+dbK6MmbAGGHkooP75ZonYiVHcd7UP AMb+hx/keVnnPqQE5Cwp1lLOG6qSypjcde0WAumNHE9WSqTxlkKuYbk38UY5FB+dbkgcDhhXg pTylA3x4847o37NepSni9ELROwJ5x4ySniKO8XUf+QKtLrpFGC254zOVv7wI0ogeWwoC+RMAP Yx2U5fLcBdgM0Em7HJ/B/GfzIVpi+lSWJh3uBSXlhAAikL1F8c4Ci Am Mittwoch, dem 09.07.2025 um 15:17 +0200 schrieb Thomas Wei=C3=9Fschuh: > Hi Bert, >=20 > On Wed, Jul 09, 2025 at 02:42:15PM +0200, Bert Karwatzki wrote: > > Recently I found that my RAM has an error (memtest86+ reproducibly rep= orts > > a failing address) (this error may lead to random crashes every few da= ys).=20 > > To further investigate the issue I tried using memtester which needs a= ccess=20 > > to /dev/mem and so I recompiled linux next-20250708 with CONFIG_DEMEM= =3Dy=20 > > and found a strange and unusual side effect: > >=20 > > a) the time displayed by xfce is stuck at 1.1.1970 01:00 (UTC + 1) > > b) most certificates in firefox-esr fail to work due to the date being= 1.1.1970=20 > > (this includes www.google.de, www.duckduckgo.com, wikipedia and youtub= e and many more) > > c) some certificates in firefox-esr still work (kernel.org, xkcd.com, = www.spiegel.de) > > d) the shell built-in time (and also /usr/bin/time) fail to work, e.g. > > $ time sleep 5 > > real 0m0,000s > > user 0m0,000s > > sys 0m0,002s > > (even though it actually take 5 seconds for this) > > e) date still works correctly, e.g. > > $ date > > Mi 9. Jul 11:51:20 CEST 2025 > > f) This example program=20 > >=20 > > #include > > #include > > #include > >=20 > > int main() > > { > > int ret; > > struct timeval tv; > > struct timezone tz; > >=20 > > ret =3D gettimeofday(&tv, &tz); > > printf("gettimeofday returns ret =3D %d, tv.tv_sec =3D %lu tv.tv_usec= =3D %lu\n", ret, tv.tv_sec, tv.tv_usec); > >=20 > > return 0; > > } > >=20 > > gives the following output on affected versions: > >=20 > > $ > > gettimeofday returns ret =3D 0, tv.tv_sec =3D 0 tv.tv_usec =3D 0 >=20 > Thanks for the report. Can you try the fix posted by Marek [0]? > It looks like the same issue where the vDSO fastpath is unavailable on y= our > hardware but I broke the check for it. Yes, this fixes the issue for me. > If it is the same issue it still leaves the question why the fastpath is > broken by CONFIG_DEVMEM. Can you describe your setup a bit? > Are there any entries in dmesg about the tsc or the clocksource subsyste= m? =20 I use a MSI Alpha 15 B5EEK/MS-158L amd64 laptop (AMD Ryzen 7 5800H) runnin= g debian sid. When booting=C2=A0 without "tsc=3Dunstable" I get this message in dmesg (this is from next-20= 250708 with CONFIG_DEVMEM=3Dy): [ C7] clocksource: timekeeping watchdog on CPU7: Marking clocksource 't= sc' as unstable because the skew is too large: [ C7] clocksource: 'hpet' wd_nsec: 495997815 wd_n= ow: 36f24f3 wd_last: 302c799 mask: ffffffff [ C7] clocksource: 'tsc' cs_nsec: 497721239 cs_no= w: 1ea2752100 cs_last: 1e43b3e700 mask: ffffffffffffffff [ C7] clocksource: Clocksource 'tsc' skewed 17234= 24 ns (1 ms) over watchdog 'hpet' interval of 495997815 ns (495 ms) [ C7] clocksource: 'hpet' (not 'tsc') is current = clocksource. [ C7] tsc: Marking TSC unstable due to clocksource watchdog [ T233] TSC found unstable after boot, most likely due to broken BIOS. Us= e 'tsc=3Dunstable'. [ T233] sched_clock: Marking unstable (4040049255, 1223348)<-(4058551237,= -15591933) I usually boot with "tsc=3Dunstable" but the issue occurs there, too. I ca= n't say yet why this only occurs with CONFIG_DEVMEM=3Dy. Bert Karwatzki